diff --git a/src/polluck_blockchain/block.hpp b/src/polluck_blockchain/block.hpp
index 3234b92..e11cef9 100644
--- a/src/polluck_blockchain/block.hpp
+++ b/src/polluck_blockchain/block.hpp
@@ -11,6 +11,6 @@ struct Block {
     std::string hash;
 
     Block() : index(0), timestamp(0), nonce(0), data(), prev_hash(), hash() {}
-    Block(uint64_t idx, double ts, uint64_t n, const std::string& d, const std::string& pre_h, const std::string& h)
+    Block(uint64_t idx, uint64_t ts, uint64_t n, const std::string& d, const std::string& pre_h, const std::string& h)
         : index(idx), timestamp(ts), nonce(n), data(d), prev_hash(pre_h), hash(h) {}
 };
diff --git a/src/polluck_blockchain/block.pxd b/src/polluck_blockchain/block.pxd
index 9b58cb3..608700e 100644
--- a/src/polluck_blockchain/block.pxd
+++ b/src/polluck_blockchain/block.pxd
@@ -4,7 +4,7 @@ from libc cimport stdint
 cdef extern from "block.hpp" namespace "":
     cdef cppclass Block:
         stdint.uint64_t index
-        double timestamp
+        stdint.uint64_t timestamp
         stdint.uint64_t nonce
         string data
         string prev_hash
diff --git a/src/polluck_blockchain/placeholder_native.cpp b/src/polluck_blockchain/placeholder_native.cpp
index 271d6ec..adce004 100644
--- a/src/polluck_blockchain/placeholder_native.cpp
+++ b/src/polluck_blockchain/placeholder_native.cpp
@@ -1171,6 +1171,7 @@ static int __Pyx_init_co_variables(void) {
     #endif
     
 #include <unordered_map>
+#include <stdlib.h>
 #ifdef _OPENMP
 #include <omp.h>
 #endif /* _OPENMP */
@@ -1553,8 +1554,8 @@ static const char* const __pyx_f[] = {
 
 /* #### Code section: numeric_typedefs ### */
 
-/* "polluck_blockchain/placeholder_native.pyx":22
- * from cython.operator import postincrement, dereference
+/* "polluck_blockchain/placeholder_native.pyx":25
+ * 
  * 
  * ctypedef unsigned long ULong             # <<<<<<<<<<<<<<
  * ctypedef unordered_map[uint64_t, Block*] BcHashmap
@@ -1567,18 +1568,31 @@ typedef unsigned long __pyx_t_18polluck_blockchain_18placeholder_native_ULong;
 /*--- Type declarations ---*/
 struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock;
 struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain;
+struct __pyx_t_18polluck_blockchain_18placeholder_native_SerializeResult;
 struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_ptr;
 
-/* "polluck_blockchain/placeholder_native.pyx":23
+/* "polluck_blockchain/placeholder_native.pyx":26
  * 
  * ctypedef unsigned long ULong
  * ctypedef unordered_map[uint64_t, Block*] BcHashmap             # <<<<<<<<<<<<<<
  * 
- * cdef timestamp_to_datetime(double ts):
+ * cdef timestamp_to_datetime(uint64_t ts):
 */
 typedef std::unordered_map<uint64_t,::Block *>  __pyx_t_18polluck_blockchain_18placeholder_native_BcHashmap;
 
-/* "polluck_blockchain/placeholder_native.pyx":82
+/* "polluck_blockchain/placeholder_native.pyx":51
+ *     out[7] = v & 0xFF
+ * 
+ * cdef struct SerializeResult:             # <<<<<<<<<<<<<<
+ *     unsigned char *ptr
+ *     size_t size
+*/
+struct __pyx_t_18polluck_blockchain_18placeholder_native_SerializeResult {
+  unsigned char *ptr;
+  size_t size;
+};
+
+/* "polluck_blockchain/placeholder_native.pyx":97
  * 
  *     @staticmethod
  *     cdef PyBlock from_ptr(Block *block, bint owner=False):             # <<<<<<<<<<<<<<
@@ -1590,8 +1604,8 @@ struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_pt
   int owner;
 };
 
-/* "polluck_blockchain/placeholder_native.pyx":33
- * 
+/* "polluck_blockchain/placeholder_native.pyx":55
+ *     size_t size
  * 
  * cdef class PyBlock:             # <<<<<<<<<<<<<<
  *     cdef:
@@ -1605,7 +1619,7 @@ struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock {
 };
 
 
-/* "polluck_blockchain/placeholder_native.pyx":157
+/* "polluck_blockchain/placeholder_native.pyx":225
  * 
  * 
  * cdef class Blockchain:             # <<<<<<<<<<<<<<
@@ -1623,8 +1637,8 @@ struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain {
 
 
 
-/* "polluck_blockchain/placeholder_native.pyx":33
- * 
+/* "polluck_blockchain/placeholder_native.pyx":55
+ *     size_t size
  * 
  * cdef class PyBlock:             # <<<<<<<<<<<<<<
  *     cdef:
@@ -1633,11 +1647,12 @@ struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain {
 
 struct __pyx_vtabstruct_18polluck_blockchain_18placeholder_native_PyBlock {
   struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *(*from_ptr)(::Block *, struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_ptr *__pyx_optional_args);
+  struct __pyx_t_18polluck_blockchain_18placeholder_native_SerializeResult (*bytes_serialize_c)(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *);
 };
 static struct __pyx_vtabstruct_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_vtabptr_18polluck_blockchain_18placeholder_native_PyBlock;
 
 
-/* "polluck_blockchain/placeholder_native.pyx":157
+/* "polluck_blockchain/placeholder_native.pyx":225
  * 
  * 
  * cdef class Blockchain:             # <<<<<<<<<<<<<<
@@ -2037,12 +2052,6 @@ static CYTHON_INLINE int __Pyx_ParseKeywords(
 static void __Pyx_RaiseArgtupleInvalid(const char* func_name, int exact,
     Py_ssize_t num_min, Py_ssize_t num_max, Py_ssize_t num_found);
 
-/* PyMemoryError_Check.proto */
-#define __Pyx_PyExc_MemoryError_Check(obj)  __Pyx_TypeCheck(obj, PyExc_MemoryError)
-
-/* RaiseException.export */
-static void __Pyx_Raise(PyObject *type, PyObject *value, PyObject *tb, PyObject *cause);
-
 /* KeywordStringCheck.proto */
 static CYTHON_INLINE int __Pyx_CheckKeywordStrings(const char* function_name, PyObject *kw);
 
@@ -2102,9 +2111,47 @@ static CYTHON_INLINE PyObject* __Pyx_decode_cpp_string(
 /* RejectKeywords.export */
 static void __Pyx_RejectKeywords(const char* function_name, PyObject *kwds);
 
+/* GetException.proto */
+#if CYTHON_FAST_THREAD_STATE
+#define __Pyx_GetException(type, value, tb)  __Pyx__GetException(__pyx_tstate, type, value, tb)
+static int __Pyx__GetException(PyThreadState *tstate, PyObject **type, PyObject **value, PyObject **tb);
+#else
+static int __Pyx_GetException(PyObject **type, PyObject **value, PyObject **tb);
+#endif
+
+/* SwapException.proto */
+#if CYTHON_FAST_THREAD_STATE
+#define __Pyx_ExceptionSwap(type, value, tb)  __Pyx__ExceptionSwap(__pyx_tstate, type, value, tb)
+static CYTHON_INLINE void __Pyx__ExceptionSwap(PyThreadState *tstate, PyObject **type, PyObject **value, PyObject **tb);
+#else
+static CYTHON_INLINE void __Pyx_ExceptionSwap(PyObject **type, PyObject **value, PyObject **tb);
+#endif
+
+/* GetTopmostException.proto (used by SaveResetException) */
+#if CYTHON_USE_EXC_INFO_STACK && CYTHON_FAST_THREAD_STATE
+static _PyErr_StackItem * __Pyx_PyErr_GetTopmostException(PyThreadState *tstate);
+#endif
+
+/* SaveResetException.proto */
+#if CYTHON_FAST_THREAD_STATE
+#define __Pyx_ExceptionSave(type, value, tb)  __Pyx__ExceptionSave(__pyx_tstate, type, value, tb)
+static CYTHON_INLINE void __Pyx__ExceptionSave(PyThreadState *tstate, PyObject **type, PyObject **value, PyObject **tb);
+#define __Pyx_ExceptionReset(type, value, tb)  __Pyx__ExceptionReset(__pyx_tstate, type, value, tb)
+static CYTHON_INLINE void __Pyx__ExceptionReset(PyThreadState *tstate, PyObject *type, PyObject *value, PyObject *tb);
+#else
+#define __Pyx_ExceptionSave(type, value, tb)   PyErr_GetExcInfo(type, value, tb)
+#define __Pyx_ExceptionReset(type, value, tb)  PyErr_SetExcInfo(type, value, tb)
+#endif
+
 /* PyTypeError_Check.proto */
 #define __Pyx_PyExc_TypeError_Check(obj)  __Pyx_TypeCheck(obj, PyExc_TypeError)
 
+/* RaiseException.export */
+static void __Pyx_Raise(PyObject *type, PyObject *value, PyObject *tb, PyObject *cause);
+
+/* PyMemoryError_Check.proto */
+#define __Pyx_PyExc_MemoryError_Check(obj)  __Pyx_TypeCheck(obj, PyExc_MemoryError)
+
 /* PyIndexError_Check.proto */
 #define __Pyx_PyExc_IndexError_Check(obj)  __Pyx_TypeCheck(obj, PyExc_IndexError)
 
@@ -2395,9 +2442,6 @@ static void __Pyx_CppExn2PyErr() {
 }
 #endif
 
-/* CIntFromPy.proto */
-static CYTHON_INLINE uint64_t __Pyx_PyLong_As_uint64_t(PyObject *);
-
 /* PyObjectVectorCallKwBuilder.proto (used by CIntToPy) */
 CYTHON_UNUSED static int __Pyx_VectorcallBuilder_AddArg_Check(PyObject *key, PyObject *value, PyObject *builder, PyObject **args, int n);
 #if CYTHON_VECTORCALL
@@ -2419,6 +2463,9 @@ static int __Pyx_VectorcallBuilder_AddArgStr(const char *key, PyObject *value, P
 /* CIntToPy.proto */
 static CYTHON_INLINE PyObject* __Pyx_PyLong_From_uint64_t(uint64_t value);
 
+/* CIntFromPy.proto */
+static CYTHON_INLINE uint64_t __Pyx_PyLong_As_uint64_t(PyObject *);
+
 /* FormatTypeName.proto */
 #if CYTHON_COMPILING_IN_LIMITED_API
 typedef PyObject *__Pyx_TypeName;
@@ -2532,6 +2579,7 @@ static int __Pyx_State_RemoveModule(void*);
 #define __PYX_TYPE_MODULE_PREFIX __PYX_ABI_MODULE_NAME "."
 
 static struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_f_18polluck_blockchain_18placeholder_native_7PyBlock_from_ptr(::Block *__pyx_v_block, struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_ptr *__pyx_optional_args); /* proto*/
+static struct __pyx_t_18polluck_blockchain_18placeholder_native_SerializeResult __pyx_f_18polluck_blockchain_18placeholder_native_7PyBlock_bytes_serialize_c(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto*/
 static ::Block *__pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_get_block_c(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, uint64_t __pyx_v_idx); /* proto*/
 static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, ::Block *__pyx_v_block); /* proto*/
 
@@ -2553,8 +2601,11 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
 
 /* Module declarations from "libcpp.unordered_map" */
 
+/* Module declarations from "libc.stdlib" */
+
 /* Module declarations from "polluck_blockchain.placeholder_native" */
-static PyObject *__pyx_f_18polluck_blockchain_18placeholder_native_timestamp_to_datetime(double); /*proto*/
+static PyObject *__pyx_f_18polluck_blockchain_18placeholder_native_timestamp_to_datetime(uint64_t); /*proto*/
+static int __pyx_f_18polluck_blockchain_18placeholder_native_serialize_uint64(unsigned char *, unsigned PY_LONG_LONG); /*proto*/
 static std::string __pyx_convert_string_from_py_6libcpp_6string_std__in_string(PyObject *); /*proto*/
 static CYTHON_INLINE PyObject *__pyx_convert_PyObject_string_to_py_6libcpp_6string_std__in_string(std::string const &); /*proto*/
 static CYTHON_INLINE PyObject *__pyx_convert_PyUnicode_string_to_py_6libcpp_6string_std__in_string(std::string const &); /*proto*/
@@ -2582,8 +2633,9 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4da
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_9prev_hash___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_5nonce___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4hash___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_10__reduce_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_12__setstate_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self, CYTHON_UNUSED PyObject *__pyx_v___pyx_state); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_10bytes_serialize(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_12__reduce_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_14__setstate_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self, CYTHON_UNUSED PyObject *__pyx_v___pyx_state); /* proto */
 static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cinit__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
 static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_2__init__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, CYTHON_UNUSED PyObject *__pyx_v_args, CYTHON_UNUSED PyObject *__pyx_v_kwargs); /* proto */
 static void __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_4__dealloc__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
@@ -2626,8 +2678,8 @@ typedef struct {
   __Pyx_CachedCFunction __pyx_umethod_PyDict_Type_pop;
   __Pyx_CachedCFunction __pyx_umethod_PyDict_Type_values;
   PyObject *__pyx_tuple[1];
-  PyObject *__pyx_codeobj_tab[8];
-  PyObject *__pyx_string_tab[89];
+  PyObject *__pyx_codeobj_tab[9];
+  PyObject *__pyx_string_tab[92];
   PyObject *__pyx_number_tab[4];
 /* #### Code section: module_state_contents ### */
 /* CommonTypesMetaclass.module_state_decls */
@@ -2669,36 +2721,36 @@ static __pyx_mstatetype __pyx_mstate_global_static =
 static __pyx_mstatetype * const __pyx_mstate_global = &__pyx_mstate_global_static;
 #endif
 /* #### Code section: constant_name_defines ### */
-#define __pyx_kp_u_Allocation_of_block_object_faile __pyx_string_tab[0]
-#define __pyx_kp_u_Could_not_allocate_hasmap __pyx_string_tab[1]
-#define __pyx_kp_u_Create_a_genesis_block_first __pyx_string_tab[2]
-#define __pyx_kp_u_Index_value_is_out_of_bounds __pyx_string_tab[3]
-#define __pyx_kp_u_PyBlock __pyx_string_tab[4]
-#define __pyx_kp_u_UTF_8 __pyx_string_tab[5]
-#define __pyx_kp_u__2 __pyx_string_tab[6]
-#define __pyx_kp_u__3 __pyx_string_tab[7]
-#define __pyx_kp_u_d __pyx_string_tab[8]
-#define __pyx_kp_u_disable __pyx_string_tab[9]
-#define __pyx_kp_u_enable __pyx_string_tab[10]
-#define __pyx_kp_u_gc __pyx_string_tab[11]
-#define __pyx_kp_u_isenabled __pyx_string_tab[12]
-#define __pyx_kp_u_no_default___reduce___due_to_non __pyx_string_tab[13]
-#define __pyx_kp_u_src_polluck_blockchain_placehold __pyx_string_tab[14]
-#define __pyx_kp_u_stringsource __pyx_string_tab[15]
-#define __pyx_n_u_Blockchain __pyx_string_tab[16]
-#define __pyx_n_u_Blockchain___reduce_cython __pyx_string_tab[17]
-#define __pyx_n_u_Blockchain___setstate_cython __pyx_string_tab[18]
-#define __pyx_n_u_Blockchain_create_genesis_block __pyx_string_tab[19]
-#define __pyx_n_u_Blockchain_get_block __pyx_string_tab[20]
-#define __pyx_n_u_Blockchain_new_block __pyx_string_tab[21]
-#define __pyx_n_u_Blockchain_print_key_value_pair __pyx_string_tab[22]
-#define __pyx_n_u_PyBlock_2 __pyx_string_tab[23]
-#define __pyx_n_u_PyBlock___reduce_cython __pyx_string_tab[24]
-#define __pyx_n_u_PyBlock___setstate_cython __pyx_string_tab[25]
-#define __pyx_n_u_Pyx_PyDict_NextRef __pyx_string_tab[26]
-#define __pyx_n_u_TIMEZONE_UTC __pyx_string_tab[27]
-#define __pyx_n_u_asyncio_coroutines __pyx_string_tab[28]
-#define __pyx_n_u_block __pyx_string_tab[29]
+#define __pyx_kp_u_Could_not_allocate_hasmap __pyx_string_tab[0]
+#define __pyx_kp_u_Create_a_genesis_block_first __pyx_string_tab[1]
+#define __pyx_kp_u_Index_value_is_out_of_bounds __pyx_string_tab[2]
+#define __pyx_kp_u_PyBlock __pyx_string_tab[3]
+#define __pyx_kp_u_UTF_8 __pyx_string_tab[4]
+#define __pyx_kp_u__2 __pyx_string_tab[5]
+#define __pyx_kp_u__3 __pyx_string_tab[6]
+#define __pyx_kp_u_disable __pyx_string_tab[7]
+#define __pyx_kp_u_enable __pyx_string_tab[8]
+#define __pyx_kp_u_gc __pyx_string_tab[9]
+#define __pyx_kp_u_isenabled __pyx_string_tab[10]
+#define __pyx_kp_u_no_default___reduce___due_to_non __pyx_string_tab[11]
+#define __pyx_kp_u_src_polluck_blockchain_placehold __pyx_string_tab[12]
+#define __pyx_kp_u_stringsource __pyx_string_tab[13]
+#define __pyx_n_u_Blockchain __pyx_string_tab[14]
+#define __pyx_n_u_Blockchain___reduce_cython __pyx_string_tab[15]
+#define __pyx_n_u_Blockchain___setstate_cython __pyx_string_tab[16]
+#define __pyx_n_u_Blockchain_create_genesis_block __pyx_string_tab[17]
+#define __pyx_n_u_Blockchain_get_block __pyx_string_tab[18]
+#define __pyx_n_u_Blockchain_new_block __pyx_string_tab[19]
+#define __pyx_n_u_Blockchain_print_key_value_pair __pyx_string_tab[20]
+#define __pyx_n_u_PyBlock_2 __pyx_string_tab[21]
+#define __pyx_n_u_PyBlock___reduce_cython __pyx_string_tab[22]
+#define __pyx_n_u_PyBlock___setstate_cython __pyx_string_tab[23]
+#define __pyx_n_u_PyBlock_bytes_serialize __pyx_string_tab[24]
+#define __pyx_n_u_Pyx_PyDict_NextRef __pyx_string_tab[25]
+#define __pyx_n_u_TIMEZONE_UTC __pyx_string_tab[26]
+#define __pyx_n_u_asyncio_coroutines __pyx_string_tab[27]
+#define __pyx_n_u_block __pyx_string_tab[28]
+#define __pyx_n_u_bytes_serialize __pyx_string_tab[29]
 #define __pyx_n_u_cline_in_traceback __pyx_string_tab[30]
 #define __pyx_n_u_create_genesis_block __pyx_string_tab[31]
 #define __pyx_n_u_data __pyx_string_tab[32]
@@ -2723,14 +2775,14 @@ static __pyx_mstatetype * const __pyx_mstate_global = &__pyx_mstate_global_stati
 #define __pyx_n_u_new_block __pyx_string_tab[51]
 #define __pyx_n_u_new_idx __pyx_string_tab[52]
 #define __pyx_n_u_nonce __pyx_string_tab[53]
-#define __pyx_n_u_pack __pyx_string_tab[54]
-#define __pyx_n_u_polluck_blockchain_placeholder_n __pyx_string_tab[55]
-#define __pyx_n_u_pop __pyx_string_tab[56]
-#define __pyx_n_u_prev_block __pyx_string_tab[57]
-#define __pyx_n_u_prev_hash __pyx_string_tab[58]
-#define __pyx_n_u_previous_hash __pyx_string_tab[59]
-#define __pyx_n_u_print __pyx_string_tab[60]
-#define __pyx_n_u_print_key_value_pair __pyx_string_tab[61]
+#define __pyx_n_u_polluck_blockchain_placeholder_n __pyx_string_tab[54]
+#define __pyx_n_u_pop __pyx_string_tab[55]
+#define __pyx_n_u_prev_block __pyx_string_tab[56]
+#define __pyx_n_u_prev_hash __pyx_string_tab[57]
+#define __pyx_n_u_previous_hash __pyx_string_tab[58]
+#define __pyx_n_u_print __pyx_string_tab[59]
+#define __pyx_n_u_print_key_value_pair __pyx_string_tab[60]
+#define __pyx_n_u_ptr __pyx_string_tab[61]
 #define __pyx_n_u_py_block __pyx_string_tab[62]
 #define __pyx_n_u_pyx_state __pyx_string_tab[63]
 #define __pyx_n_u_pyx_vtable __pyx_string_tab[64]
@@ -2740,24 +2792,27 @@ static __pyx_mstatetype * const __pyx_mstate_global = &__pyx_mstate_global_stati
 #define __pyx_n_u_reduce_ex __pyx_string_tab[68]
 #define __pyx_n_u_repr __pyx_string_tab[69]
 #define __pyx_n_u_self __pyx_string_tab[70]
-#define __pyx_n_u_set_name __pyx_string_tab[71]
-#define __pyx_n_u_setdefault __pyx_string_tab[72]
-#define __pyx_n_u_setstate __pyx_string_tab[73]
-#define __pyx_n_u_setstate_cython __pyx_string_tab[74]
-#define __pyx_n_u_struct __pyx_string_tab[75]
-#define __pyx_n_u_test __pyx_string_tab[76]
-#define __pyx_n_u_time __pyx_string_tab[77]
-#define __pyx_n_u_timestamp __pyx_string_tab[78]
-#define __pyx_n_u_values __pyx_string_tab[79]
-#define __pyx_kp_b_ __pyx_string_tab[80]
-#define __pyx_kp_b_0 __pyx_string_tab[81]
-#define __pyx_kp_b_Genesis_Block __pyx_string_tab[82]
-#define __pyx_kp_b_dummy_hash __pyx_string_tab[83]
-#define __pyx_kp_b_iso88591_A_4r_3d_D_AQ_D_AQ_iq_Q __pyx_string_tab[84]
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- *                 raise MemoryError("Allocation of block object failed")
+    /* "polluck_blockchain/placeholder_native.pyx":86
+ *                 raise MemoryError()
  * 
  *             self.ptr_owner = True             # <<<<<<<<<<<<<<
  * 
@@ -3711,7 +3830,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock___cinit__
 */
     __pyx_v_self->ptr_owner = 1;
 
-    /* "polluck_blockchain/placeholder_native.pyx":52
+    /* "polluck_blockchain/placeholder_native.pyx":74
  *     ):
  *         self.ptr_owner = False
  *         if not from_ptr:             # <<<<<<<<<<<<<<
@@ -3720,7 +3839,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock___cinit__
 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":44
+  /* "polluck_blockchain/placeholder_native.pyx":66
  *         bint ptr_owner
  * 
  *     def __cinit__(self,             # <<<<<<<<<<<<<<
@@ -3743,12 +3862,12 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock___cinit__
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":66
+/* "polluck_blockchain/placeholder_native.pyx":88
  *             self.ptr_owner = True
  * 
  *     def __init__(self, *args, **kwargs):             # <<<<<<<<<<<<<<
  *         pass
- *         # self._index = index
+ * 
 */
 
 /* Python wrapper */
@@ -3791,8 +3910,8 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_2__init__
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":76
- *         # self._hash = "".encode("UTF-8")
+/* "polluck_blockchain/placeholder_native.pyx":91
+ *         pass
  * 
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  *         if self.BlockC is not NULL and self.ptr_owner is True:
@@ -3816,7 +3935,7 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__deall
   int __pyx_t_1;
   int __pyx_t_2;
 
-  /* "polluck_blockchain/placeholder_native.pyx":77
+  /* "polluck_blockchain/placeholder_native.pyx":92
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@@ -3834,7 +3953,7 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__deall
   __pyx_L4_bool_binop_done:;
   if (__pyx_t_1) {
 
-    /* "polluck_blockchain/placeholder_native.pyx":78
+    /* "polluck_blockchain/placeholder_native.pyx":93
  *     def __dealloc__(self):
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@@ -3843,7 +3962,7 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__deall
 */
     delete __pyx_v_self->BlockC;
 
-    /* "polluck_blockchain/placeholder_native.pyx":79
+    /* "polluck_blockchain/placeholder_native.pyx":94
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@@ -3852,7 +3971,7 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__deall
 */
     __pyx_v_self->BlockC = NULL;
 
-    /* "polluck_blockchain/placeholder_native.pyx":77
+    /* "polluck_blockchain/placeholder_native.pyx":92
  * 
  *     def __dealloc__(self):
  *         if self.BlockC is not NULL and self.ptr_owner is True:             # <<<<<<<<<<<<<<
@@ -3861,8 +3980,8 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__deall
 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":76
- *         # self._hash = "".encode("UTF-8")
+  /* "polluck_blockchain/placeholder_native.pyx":91
+ *         pass
  * 
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  *         if self.BlockC is not NULL and self.ptr_owner is True:
@@ -3872,7 +3991,7 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__deall
   /* function exit code */
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":81
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@@ -3882,7 +4001,7 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__deall
 
 static struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_f_18polluck_blockchain_18placeholder_native_7PyBlock_from_ptr(::Block *__pyx_v_block, struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_ptr *__pyx_optional_args) {
 
-  /* "polluck_blockchain/placeholder_native.pyx":82
+  /* "polluck_blockchain/placeholder_native.pyx":97
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@@ -3908,77 +4027,77 @@ static struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx
     }
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-  /* "polluck_blockchain/placeholder_native.pyx":85
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   __pyx_t_4 = 0;
 
-  /* "polluck_blockchain/placeholder_native.pyx":91
+  /* "polluck_blockchain/placeholder_native.pyx":106
  *             True,
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@@ -3987,7 +4106,7 @@ static struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx
 */
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-  /* "polluck_blockchain/placeholder_native.pyx":92
+  /* "polluck_blockchain/placeholder_native.pyx":107
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-  /* "polluck_blockchain/placeholder_native.pyx":94
+  /* "polluck_blockchain/placeholder_native.pyx":109
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-  /* "polluck_blockchain/placeholder_native.pyx":81
+  /* "polluck_blockchain/placeholder_native.pyx":96
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   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":96
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 }
 
-/* "polluck_blockchain/placeholder_native.pyx":176
- *     # TODO add entries of map
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 /* Python wrapper */
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-  /* "polluck_blockchain/placeholder_native.pyx":177
- *     # ownership is typically not transferred from the Blockchain extension class
+  /* "polluck_blockchain/placeholder_native.pyx":244
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 */
     __pyx_v_self->_chain = NULL;
 
-    /* "polluck_blockchain/placeholder_native.pyx":178
- *     def __dealloc__(self):
+    /* "polluck_blockchain/placeholder_native.pyx":245
+ *         # ownership is typically not transferred from the Blockchain extension class
  *         cdef BcHashmap.iterator it = self._chain.begin()
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 */
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-  /* "polluck_blockchain/placeholder_native.pyx":176
- *     # TODO add entries of map
- *     # ownership is typically not transferred from the Blockchain extension class
+  /* "polluck_blockchain/placeholder_native.pyx":242
+ *         pass
+ * 
  *     def __dealloc__(self):             # <<<<<<<<<<<<<<
+ *         # ownership is typically not transferred from the Blockchain extension class
  *         cdef BcHashmap.iterator it = self._chain.begin()
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 */
 
   /* function exit code */
 }
 
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  * 
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 static Py_ssize_t __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_6__len__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self) {
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-  /* "polluck_blockchain/placeholder_native.pyx":187
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   goto __pyx_L0;
 
-  /* "polluck_blockchain/placeholder_native.pyx":186
+  /* "polluck_blockchain/placeholder_native.pyx":253
  *             self._chain = NULL
  * 
  *     def __len__(self):             # <<<<<<<<<<<<<<
@@ -5163,7 +5646,7 @@ static Py_ssize_t __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchai
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":189
+/* "polluck_blockchain/placeholder_native.pyx":256
  *         return self._index + 1
  * 
  *     def print_key_value_pair(self):             # <<<<<<<<<<<<<<
@@ -5230,7 +5713,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("print_key_value_pair", 0);
 
-  /* "polluck_blockchain/placeholder_native.pyx":190
+  /* "polluck_blockchain/placeholder_native.pyx":257
  * 
  *     def print_key_value_pair(self):
  *         cdef BcHashmap.iterator it = self._chain.begin()             # <<<<<<<<<<<<<<
@@ -5239,7 +5722,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
 */
   __pyx_v_it = __pyx_v_self->_chain->begin();
 
-  /* "polluck_blockchain/placeholder_native.pyx":192
+  /* "polluck_blockchain/placeholder_native.pyx":259
  *         cdef BcHashmap.iterator it = self._chain.begin()
  *         cdef Block *block
  *         while it != self._chain.end():             # <<<<<<<<<<<<<<
@@ -5250,7 +5733,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
     __pyx_t_1 = (__pyx_v_it != __pyx_v_self->_chain->end());
     if (!__pyx_t_1) break;
 
-    /* "polluck_blockchain/placeholder_native.pyx":193
+    /* "polluck_blockchain/placeholder_native.pyx":260
  *         cdef Block *block
  *         while it != self._chain.end():
  *             print(dereference(it).first)             # <<<<<<<<<<<<<<
@@ -5258,7 +5741,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
  *             py_block = PyBlock.from_ptr(block)
 */
     __pyx_t_3 = NULL;
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+    __pyx_t_4 = __Pyx_PyLong_From_uint64_t((*__pyx_v_it).first); if (unlikely(!__pyx_t_4)) __PYX_ERR(0, 260, __pyx_L1_error)
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@@ -5266,12 +5749,12 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
       __pyx_t_2 = __Pyx_PyObject_FastCall((PyObject*)__pyx_builtin_print, __pyx_callargs+__pyx_t_5, (2-__pyx_t_5) | (__pyx_t_5*__Pyx_PY_VECTORCALL_ARGUMENTS_OFFSET));
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-      if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 193, __pyx_L1_error)
+      if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 260, __pyx_L1_error)
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     __Pyx_DECREF(__pyx_t_2); __pyx_t_2 = 0;
 
-    /* "polluck_blockchain/placeholder_native.pyx":194
+    /* "polluck_blockchain/placeholder_native.pyx":261
  *         while it != self._chain.end():
  *             print(dereference(it).first)
  *             block = dereference(it).second             # <<<<<<<<<<<<<<
@@ -5281,19 +5764,19 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
     __pyx_t_6 = (*__pyx_v_it).second;
     __pyx_v_block = __pyx_t_6;
 
-    /* "polluck_blockchain/placeholder_native.pyx":195
+    /* "polluck_blockchain/placeholder_native.pyx":262
  *             print(dereference(it).first)
  *             block = dereference(it).second
  *             py_block = PyBlock.from_ptr(block)             # <<<<<<<<<<<<<<
  *             print(py_block)
  *             postincrement(it)
 */
-    __pyx_t_2 = ((PyObject *)__pyx_vtabptr_18polluck_blockchain_18placeholder_native_PyBlock->from_ptr(__pyx_v_block, NULL)); if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 195, __pyx_L1_error)
+    __pyx_t_2 = ((PyObject *)__pyx_vtabptr_18polluck_blockchain_18placeholder_native_PyBlock->from_ptr(__pyx_v_block, NULL)); if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 262, __pyx_L1_error)
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     __Pyx_XDECREF_SET(__pyx_v_py_block, ((struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *)__pyx_t_2));
     __pyx_t_2 = 0;
 
-    /* "polluck_blockchain/placeholder_native.pyx":196
+    /* "polluck_blockchain/placeholder_native.pyx":263
  *             block = dereference(it).second
  *             py_block = PyBlock.from_ptr(block)
  *             print(py_block)             # <<<<<<<<<<<<<<
@@ -5306,12 +5789,12 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
       PyObject *__pyx_callargs[2] = {__pyx_t_4, ((PyObject *)__pyx_v_py_block)};
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-      if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 196, __pyx_L1_error)
+      if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 263, __pyx_L1_error)
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     __Pyx_DECREF(__pyx_t_2); __pyx_t_2 = 0;
 
-    /* "polluck_blockchain/placeholder_native.pyx":197
+    /* "polluck_blockchain/placeholder_native.pyx":264
  *             py_block = PyBlock.from_ptr(block)
  *             print(py_block)
  *             postincrement(it)             # <<<<<<<<<<<<<<
@@ -5321,7 +5804,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
     (void)((__pyx_v_it++));
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":189
+  /* "polluck_blockchain/placeholder_native.pyx":256
  *         return self._index + 1
  * 
  *     def print_key_value_pair(self):             # <<<<<<<<<<<<<<
@@ -5345,7 +5828,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":199
+/* "polluck_blockchain/placeholder_native.pyx":266
  *             postincrement(it)
  * 
  *     @property             # <<<<<<<<<<<<<<
@@ -5377,7 +5860,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("__get__", 0);
 
-  /* "polluck_blockchain/placeholder_native.pyx":201
+  /* "polluck_blockchain/placeholder_native.pyx":268
  *     @property
  *     def genesis_done(self):
  *         return self._genesis_done             # <<<<<<<<<<<<<<
@@ -5385,13 +5868,13 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
  *     @property
 */
   __Pyx_XDECREF(__pyx_r);
-  __pyx_t_1 = __Pyx_PyBool_FromLong(__pyx_v_self->_genesis_done); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 201, __pyx_L1_error)
+  __pyx_t_1 = __Pyx_PyBool_FromLong(__pyx_v_self->_genesis_done); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 268, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_1);
   __pyx_r = __pyx_t_1;
   __pyx_t_1 = 0;
   goto __pyx_L0;
 
-  /* "polluck_blockchain/placeholder_native.pyx":199
+  /* "polluck_blockchain/placeholder_native.pyx":266
  *             postincrement(it)
  * 
  *     @property             # <<<<<<<<<<<<<<
@@ -5410,7 +5893,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":203
+/* "polluck_blockchain/placeholder_native.pyx":270
  *         return self._genesis_done
  * 
  *     @property             # <<<<<<<<<<<<<<
@@ -5442,7 +5925,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("__get__", 0);
 
-  /* "polluck_blockchain/placeholder_native.pyx":205
+  /* "polluck_blockchain/placeholder_native.pyx":272
  *     @property
  *     def index(self):
  *         return self._index             # <<<<<<<<<<<<<<
@@ -5450,13 +5933,13 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
  *     # TODO error handling
 */
   __Pyx_XDECREF(__pyx_r);
-  __pyx_t_1 = __Pyx_PyLong_From_uint64_t(__pyx_v_self->_index); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 205, __pyx_L1_error)
+  __pyx_t_1 = __Pyx_PyLong_From_uint64_t(__pyx_v_self->_index); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 272, __pyx_L1_error)
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   __pyx_r = __pyx_t_1;
   __pyx_t_1 = 0;
   goto __pyx_L0;
 
-  /* "polluck_blockchain/placeholder_native.pyx":203
+  /* "polluck_blockchain/placeholder_native.pyx":270
  *         return self._genesis_done
  * 
  *     @property             # <<<<<<<<<<<<<<
@@ -5475,7 +5958,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":208
+/* "polluck_blockchain/placeholder_native.pyx":275
  * 
  *     # TODO error handling
  *     cdef Block* get_block_c(self, uint64_t idx):             # <<<<<<<<<<<<<<
@@ -5486,7 +5969,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
 static ::Block *__pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_get_block_c(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, uint64_t __pyx_v_idx) {
   ::Block *__pyx_r;
 
-  /* "polluck_blockchain/placeholder_native.pyx":209
+  /* "polluck_blockchain/placeholder_native.pyx":276
  *     # TODO error handling
  *     cdef Block* get_block_c(self, uint64_t idx):
  *         return self._chain[0][idx]             # <<<<<<<<<<<<<<
@@ -5496,7 +5979,7 @@ static ::Block *__pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_g
   __pyx_r = ((__pyx_v_self->_chain[0])[__pyx_v_idx]);
   goto __pyx_L0;
 
-  /* "polluck_blockchain/placeholder_native.pyx":208
+  /* "polluck_blockchain/placeholder_native.pyx":275
  * 
  *     # TODO error handling
  *     cdef Block* get_block_c(self, uint64_t idx):             # <<<<<<<<<<<<<<
@@ -5509,7 +5992,7 @@ static ::Block *__pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_g
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":211
+/* "polluck_blockchain/placeholder_native.pyx":278
  *         return self._chain[0][idx]
  * 
  *     def get_block(self, idx):             # <<<<<<<<<<<<<<
@@ -5556,32 +6039,32 @@ PyObject *__pyx_args, PyObject *__pyx_kwds
   {
     PyObject ** const __pyx_pyargnames[] = {&__pyx_mstate_global->__pyx_n_u_idx,0};
     const Py_ssize_t __pyx_kwds_len = (__pyx_kwds) ? __Pyx_NumKwargs_FASTCALL(__pyx_kwds) : 0;
-    if (unlikely(__pyx_kwds_len) < 0) __PYX_ERR(0, 211, __pyx_L3_error)
+    if (unlikely(__pyx_kwds_len) < 0) __PYX_ERR(0, 278, __pyx_L3_error)
     if (__pyx_kwds_len > 0) {
       switch (__pyx_nargs) {
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         values[0] = __Pyx_ArgRef_FASTCALL(__pyx_args, 0);
-        if (!CYTHON_ASSUME_SAFE_MACROS && unlikely(!values[0])) __PYX_ERR(0, 211, __pyx_L3_error)
+        if (!CYTHON_ASSUME_SAFE_MACROS && unlikely(!values[0])) __PYX_ERR(0, 278, __pyx_L3_error)
         CYTHON_FALLTHROUGH;
         case  0: break;
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       const Py_ssize_t kwd_pos_args = __pyx_nargs;
-      if (__Pyx_ParseKeywords(__pyx_kwds, __pyx_kwvalues, __pyx_pyargnames, 0, values, kwd_pos_args, __pyx_kwds_len, "get_block", 0) < (0)) __PYX_ERR(0, 211, __pyx_L3_error)
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       for (Py_ssize_t i = __pyx_nargs; i < 1; i++) {
-        if (unlikely(!values[i])) { __Pyx_RaiseArgtupleInvalid("get_block", 1, 1, 1, i); __PYX_ERR(0, 211, __pyx_L3_error) }
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-      if (!CYTHON_ASSUME_SAFE_MACROS && unlikely(!values[0])) __PYX_ERR(0, 211, __pyx_L3_error)
+      if (!CYTHON_ASSUME_SAFE_MACROS && unlikely(!values[0])) __PYX_ERR(0, 278, __pyx_L3_error)
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     __pyx_v_idx = values[0];
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   goto __pyx_L6_skip;
   __pyx_L5_argtuple_error:;
-  __Pyx_RaiseArgtupleInvalid("get_block", 1, 1, 1, __pyx_nargs); __PYX_ERR(0, 211, __pyx_L3_error)
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@@ -5619,32 +6102,32 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   int __pyx_clineno = 0;
   __Pyx_RefNannySetupContext("get_block", 0);
 
-  /* "polluck_blockchain/placeholder_native.pyx":212
+  /* "polluck_blockchain/placeholder_native.pyx":279
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  *     def get_block(self, idx):
  *         if idx < 0 or idx > self._index:             # <<<<<<<<<<<<<<
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 */
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-  __pyx_t_3 = __Pyx_PyObject_IsTrue(__pyx_t_2); if (unlikely((__pyx_t_3 < 0))) __PYX_ERR(0, 212, __pyx_L1_error)
+  __pyx_t_2 = PyObject_RichCompare(__pyx_v_idx, __pyx_mstate_global->__pyx_int_0, Py_LT); __Pyx_XGOTREF(__pyx_t_2); if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 279, __pyx_L1_error)
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-  __pyx_t_2 = __Pyx_PyLong_From_uint64_t(__pyx_v_self->_index); if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 212, __pyx_L1_error)
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+  __pyx_t_4 = PyObject_RichCompare(__pyx_v_idx, __pyx_t_2, Py_GT); __Pyx_XGOTREF(__pyx_t_4); if (unlikely(!__pyx_t_4)) __PYX_ERR(0, 279, __pyx_L1_error)
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-  __pyx_t_3 = __Pyx_PyObject_IsTrue(__pyx_t_4); if (unlikely((__pyx_t_3 < 0))) __PYX_ERR(0, 212, __pyx_L1_error)
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-    /* "polluck_blockchain/placeholder_native.pyx":213
+    /* "polluck_blockchain/placeholder_native.pyx":280
  *     def get_block(self, idx):
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@@ -5657,14 +6140,14 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
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-      if (unlikely(!__pyx_t_4)) __PYX_ERR(0, 213, __pyx_L1_error)
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-    /* "polluck_blockchain/placeholder_native.pyx":212
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  *     def get_block(self, idx):
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@@ -5673,18 +6156,18 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":215
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  *         cdef Block *block = self.get_block_c(idx)             # <<<<<<<<<<<<<<
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 */
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+  __pyx_t_6 = __Pyx_PyLong_As_uint64_t(__pyx_v_idx); if (unlikely((__pyx_t_6 == ((uint64_t)-1)) && PyErr_Occurred())) __PYX_ERR(0, 282, __pyx_L1_error)
+  __pyx_t_7 = ((struct __pyx_vtabstruct_18polluck_blockchain_18placeholder_native_Blockchain *)__pyx_v_self->__pyx_vtab)->get_block_c(__pyx_v_self, __pyx_t_6); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 282, __pyx_L1_error)
   __pyx_v_block = __pyx_t_7;
 
-  /* "polluck_blockchain/placeholder_native.pyx":216
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  *         cdef Block *block = self.get_block_c(idx)
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+  __pyx_t_4 = ((PyObject *)__pyx_vtabptr_18polluck_blockchain_18placeholder_native_PyBlock->from_ptr(__pyx_v_block, &__pyx_t_8)); if (unlikely(!__pyx_t_4)) __PYX_ERR(0, 283, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":211
+  /* "polluck_blockchain/placeholder_native.pyx":278
  *         return self._chain[0][idx]
  * 
  *     def get_block(self, idx):             # <<<<<<<<<<<<<<
@@ -5720,7 +6203,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":218
+/* "polluck_blockchain/placeholder_native.pyx":285
  *         return PyBlock.from_ptr(block, owner=False)
  * 
  *     cdef void add_block(self, Block *block):             # <<<<<<<<<<<<<<
@@ -5730,7 +6213,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
 
 static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, ::Block *__pyx_v_block) {
 
-  /* "polluck_blockchain/placeholder_native.pyx":219
+  /* "polluck_blockchain/placeholder_native.pyx":286
  * 
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  *         self._chain[0][block.index] = block             # <<<<<<<<<<<<<<
@@ -5739,7 +6222,7 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
 */
   ((__pyx_v_self->_chain[0])[__pyx_v_block->index]) = __pyx_v_block;
 
-  /* "polluck_blockchain/placeholder_native.pyx":220
+  /* "polluck_blockchain/placeholder_native.pyx":287
  *     cdef void add_block(self, Block *block):
  *         self._chain[0][block.index] = block
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@@ -5748,7 +6231,7 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
 */
   if (__pyx_v_self->_genesis_done) {
 
-    /* "polluck_blockchain/placeholder_native.pyx":221
+    /* "polluck_blockchain/placeholder_native.pyx":288
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 */
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-    /* "polluck_blockchain/placeholder_native.pyx":220
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@@ -5766,7 +6249,7 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":218
+  /* "polluck_blockchain/placeholder_native.pyx":285
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  * 
  *     cdef void add_block(self, Block *block):             # <<<<<<<<<<<<<<
@@ -5777,7 +6260,7 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
   /* function exit code */
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":223
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-  /* "polluck_blockchain/placeholder_native.pyx":226
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  *             self._index,
- *             datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp(),             # <<<<<<<<<<<<<<
+ *             int(datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp()),             # <<<<<<<<<<<<<<
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+  __pyx_t_4 = __Pyx_PyObject_GetAttrStr(__pyx_t_3, __pyx_mstate_global->__pyx_n_u_datetime); if (unlikely(!__pyx_t_4)) __PYX_ERR(0, 293, __pyx_L1_error)
   __Pyx_GOTREF(__pyx_t_4);
   __Pyx_DECREF(__pyx_t_3); __pyx_t_3 = 0;
-  __pyx_t_3 = __Pyx_PyObject_Call(__pyx_t_4, __pyx_mstate_global->__pyx_tuple[0], NULL); if (unlikely(!__pyx_t_3)) __PYX_ERR(0, 226, __pyx_L1_error)
+  __pyx_t_3 = __Pyx_PyObject_Call(__pyx_t_4, __pyx_mstate_global->__pyx_tuple[0], NULL); if (unlikely(!__pyx_t_3)) __PYX_ERR(0, 293, __pyx_L1_error)
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@@ -5869,74 +6352,77 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
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-  /* "polluck_blockchain/placeholder_native.pyx":228
- *             datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp(),
+  /* "polluck_blockchain/placeholder_native.pyx":295
+ *             int(datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp()),
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-  /* "polluck_blockchain/placeholder_native.pyx":229
+  /* "polluck_blockchain/placeholder_native.pyx":296
  *             0,
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  *             "0".encode("UTF-8"),             # <<<<<<<<<<<<<<
  *             "".encode("UTF-8"),
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 */
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-  /* "polluck_blockchain/placeholder_native.pyx":230
+  /* "polluck_blockchain/placeholder_native.pyx":297
  *             "Genesis Block".encode("UTF-8"),
  *             "0".encode("UTF-8"),
  *             "".encode("UTF-8"),             # <<<<<<<<<<<<<<
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  *         block.hash = "dummy hash".encode("UTF-8")
 */
-  __pyx_t_9 = __pyx_convert_string_from_py_6libcpp_6string_std__in_string(__pyx_mstate_global->__pyx_kp_b_); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 230, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":224
+  /* "polluck_blockchain/placeholder_native.pyx":291
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  *     def create_genesis_block(self):
  *         cdef Block *block = new Block(             # <<<<<<<<<<<<<<
  *             self._index,
- *             datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp(),
+ *             int(datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp()),
 */
   try {
     __pyx_t_10 = new ::Block(__pyx_v_self->_index, __pyx_t_6, 0, __pyx_t_7, __pyx_t_8, __pyx_t_9);
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     __Pyx_CppExn2PyErr();
-    __PYX_ERR(0, 224, __pyx_L1_error)
+    __PYX_ERR(0, 291, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":232
+  /* "polluck_blockchain/placeholder_native.pyx":299
  *             "".encode("UTF-8"),
  *         )
  *         block.hash = "dummy hash".encode("UTF-8")             # <<<<<<<<<<<<<<
  *         self.add_block(block)
  *         self._genesis_done = True
 */
-  __pyx_t_9 = __pyx_convert_string_from_py_6libcpp_6string_std__in_string(__pyx_mstate_global->__pyx_kp_b_dummy_hash); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 232, __pyx_L1_error)
+  __pyx_t_9 = __pyx_convert_string_from_py_6libcpp_6string_std__in_string(__pyx_mstate_global->__pyx_kp_b_dummy_hash); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 299, __pyx_L1_error)
   __pyx_v_block->hash = __PYX_STD_MOVE_IF_SUPPORTED(__pyx_t_9);
 
-  /* "polluck_blockchain/placeholder_native.pyx":233
+  /* "polluck_blockchain/placeholder_native.pyx":300
  *         )
  *         block.hash = "dummy hash".encode("UTF-8")
  *         self.add_block(block)             # <<<<<<<<<<<<<<
  *         self._genesis_done = True
  * 
 */
-  ((struct __pyx_vtabstruct_18polluck_blockchain_18placeholder_native_Blockchain *)__pyx_v_self->__pyx_vtab)->add_block(__pyx_v_self, __pyx_v_block); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 233, __pyx_L1_error)
+  ((struct __pyx_vtabstruct_18polluck_blockchain_18placeholder_native_Blockchain *)__pyx_v_self->__pyx_vtab)->add_block(__pyx_v_self, __pyx_v_block); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 300, __pyx_L1_error)
 
-  /* "polluck_blockchain/placeholder_native.pyx":234
+  /* "polluck_blockchain/placeholder_native.pyx":301
  *         block.hash = "dummy hash".encode("UTF-8")
  *         self.add_block(block)
  *         self._genesis_done = True             # <<<<<<<<<<<<<<
@@ -5945,7 +6431,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
 */
   __pyx_v_self->_genesis_done = 1;
 
-  /* "polluck_blockchain/placeholder_native.pyx":223
+  /* "polluck_blockchain/placeholder_native.pyx":290
  *             self._index += 1
  * 
  *     def create_genesis_block(self):             # <<<<<<<<<<<<<<
@@ -5969,7 +6455,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":236
+/* "polluck_blockchain/placeholder_native.pyx":303
  *         self._genesis_done = True
  * 
  *     def new_block(self, data):             # <<<<<<<<<<<<<<
@@ -6016,32 +6502,32 @@ PyObject *__pyx_args, PyObject *__pyx_kwds
   {
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     const Py_ssize_t __pyx_kwds_len = (__pyx_kwds) ? __Pyx_NumKwargs_FASTCALL(__pyx_kwds) : 0;
-    if (unlikely(__pyx_kwds_len) < 0) __PYX_ERR(0, 236, __pyx_L3_error)
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     if (__pyx_kwds_len > 0) {
       switch (__pyx_nargs) {
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         case  0: break;
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-        if (unlikely(!values[i])) { __Pyx_RaiseArgtupleInvalid("new_block", 1, 1, 1, i); __PYX_ERR(0, 236, __pyx_L3_error) }
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@@ -6084,7 +6570,7 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
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-  /* "polluck_blockchain/placeholder_native.pyx":237
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  *     def new_block(self, data):
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   __pyx_t_1 = (!__pyx_v_self->_genesis_done);
   if (unlikely(__pyx_t_1)) {
 
-    /* "polluck_blockchain/placeholder_native.pyx":238
+    /* "polluck_blockchain/placeholder_native.pyx":305
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@@ -6107,14 +6593,14 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
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-      if (unlikely(!__pyx_t_2)) __PYX_ERR(0, 238, __pyx_L1_error)
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-    /* "polluck_blockchain/placeholder_native.pyx":237
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 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":240
+  /* "polluck_blockchain/placeholder_native.pyx":307
  *             raise RuntimeError("Create a genesis block first.")
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  *         cdef Block *prev_block = self.get_block_c(self._index)             # <<<<<<<<<<<<<<
  *         cdef string prev_hash = prev_block.prev_hash
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 */
-  __pyx_t_5 = ((struct __pyx_vtabstruct_18polluck_blockchain_18placeholder_native_Blockchain *)__pyx_v_self->__pyx_vtab)->get_block_c(__pyx_v_self, __pyx_v_self->_index); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 240, __pyx_L1_error)
+  __pyx_t_5 = ((struct __pyx_vtabstruct_18polluck_blockchain_18placeholder_native_Blockchain *)__pyx_v_self->__pyx_vtab)->get_block_c(__pyx_v_self, __pyx_v_self->_index); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 307, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":241
+  /* "polluck_blockchain/placeholder_native.pyx":308
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  *         cdef string prev_hash = prev_block.prev_hash             # <<<<<<<<<<<<<<
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-  /* "polluck_blockchain/placeholder_native.pyx":242
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+    PyObject *data = __Pyx_DecompressString(cstring, 965, 2);
     if (unlikely(!data)) __PYX_ERR(0, 1, __pyx_L1_error)
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-    PyObject *data = __Pyx_DecompressString(cstring, 786, 1);
+    #elif (CYTHON_COMPRESS_STRINGS) != 0 /* compression: zlib (831 bytes) */
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+    PyObject *data = __Pyx_DecompressString(cstring, 831, 1);
     if (unlikely(!data)) __PYX_ERR(0, 1, __pyx_L1_error)
     const char* const bytes = __Pyx_PyBytes_AsString(data);
     #if !CYTHON_ASSUME_SAFE_MACROS
     if (likely(bytes)); else { Py_DECREF(data); __PYX_ERR(0, 1, __pyx_L1_error) }
     #endif
-    #else /* compression: none (1422 bytes) */
-const char* const bytes = "Allocation of block object failedCould not allocate hasmapCreate a genesis block first.Index value is out of boundsPyBlock(UTF-8)?>ddisableenablegcisenabledno default __reduce__ due to non-trivial __cinit__src/polluck_blockchain/placeholder_native.pyx<stringsource>BlockchainBlockchain.__reduce_cython__Blockchain.__setstate_cython__Blockchain.create_genesis_blockBlockchain.get_blockBlockchain.new_blockBlockchain.print_key_value_pairPyBlockPyBlock.__reduce_cython__PyBlock.__setstate_cython____Pyx_PyDict_NextRefTIMEZONE_UTCasyncio.coroutinesblockcline_in_tracebackcreate_genesis_blockdatadatetimedopt_basicsdopt_basics.datetimeencodefrom_ptrfromtimestamp__func__get_block__getstate__hashlibidxindex_is_coroutineititems__main____module____name__new_blocknew_idxnoncepackpolluck_blockchain.placeholder_nativepopprev_blockprev_hashprevious_hashprintprint_key_value_pairpy_block__pyx_state__pyx_vtable____qualname____reduce____reduce_cython____reduce_ex____repr__self__set_name__setdefault__setstate____setstate_cython__struct__test__timetimestampvalues0Genesis Blockdummy hash\200A\330\010\013\2104\210r\220\022\2203\220d\230\"\230D\240\001\330\014\022\220*\230A\230Q\340\010\034\230D\240\014\250A\250Q\330\010\026\220i\230q\240\r\250Q\200A\330\010\013\2104\210t\2201\330\014\022\220,\230a\230q\340\010!\240\024\240\\\260\021\260$\260a\330\010 \240\n\250!\330\010 \240\004\240H\250B\250a\340\010\034\230I\240Q\330\014\r\330\014\024\220I\230Q\230f\240D\250\003\2504\250s\260\"\260J\270a\330\014\r\330\014\020\220\007\220q\230\001\330\014\r\330\014\016\210g\220Q\220a\340\010\014\210J\220a\220q\200A\330\010\034\230I\240Q\330\014\020\220\001\330\014\024\220I\230Q\230f\240D\250\003\2504\250s\260\"\260J\270a\330\014\r\330\014\033\2307\240!\2401\330\014\017\210w\220a\220q\330\014\016\210g\220Q\220a\340\010\r\210X\220\\\240\027\250\001\250\021\330\010\014\210J\220a\220q\330\010\014\320\014\035\230Q\200A\330\010%\240T\250\027\260\006\260a\340\010\016\210c\220\023\220D\230\007\230t\2401\330\014\021""\220\021\220,\230c\240\021\330\014\024\220L\240\003\2401\330\014\036\230i\240q\250\001\330\014\021\220\021\220!\330\014\031\230\021\230!\200\001\330\004\n\210+\220Q";
+    #else /* compression: none (1486 bytes) */
+const char* const bytes = "Could not allocate hasmapCreate a genesis block first.Index value is out of boundsPyBlock(UTF-8)?disableenablegcisenabledno default __reduce__ due to non-trivial __cinit__src/polluck_blockchain/placeholder_native.pyx<stringsource>BlockchainBlockchain.__reduce_cython__Blockchain.__setstate_cython__Blockchain.create_genesis_blockBlockchain.get_blockBlockchain.new_blockBlockchain.print_key_value_pairPyBlockPyBlock.__reduce_cython__PyBlock.__setstate_cython__PyBlock.bytes_serialize__Pyx_PyDict_NextRefTIMEZONE_UTCasyncio.coroutinesblockbytes_serializecline_in_tracebackcreate_genesis_blockdatadatetimedopt_basicsdopt_basics.datetimeencodefrom_ptrfromtimestamp__func__get_block__getstate__hashlibidxindex_is_coroutineititems__main____module____name__new_blocknew_idxnoncepolluck_blockchain.placeholder_nativepopprev_blockprev_hashprevious_hashprintprint_key_value_pairptrpy_block__pyx_state__pyx_vtable____qualname____reduce____reduce_cython____reduce_ex____repr__selfserialize_res__set_name__setdefault__setstate____setstate_cython__sizestruct__test__timetimestampvalues0Genesis Blockdummy hash\200A\330\010\013\2104\210r\220\022\2203\220d\230\"\230D\240\001\330\014\022\220*\230A\230Q\340\010\034\230D\240\014\250A\250Q\330\010\026\220i\230q\240\r\250Q\200A\330\010\013\2104\210t\2201\330\014\022\220,\230a\230q\340\010!\240\024\240\\\260\021\260$\260a\330\010 \240\n\250!\330\010 \240\004\240H\250B\250a\340\010\034\230I\240Q\330\014\r\330\014\017\210q\220\010\230\t\240\021\240&\250\004\250C\250t\2603\260b\270\n\300!\330\014\r\330\014\020\220\007\220q\230\001\330\014\r\330\014\016\210g\220Q\220a\340\010\014\210J\220a\220q\200A\340\010\t\330\014\034\230D\320 2\260!\330\014\023\220=\240\004\240B\240m\2601\340\014\020\220\001\220\035\230a\200A\330\010\034\230I\240Q\330\014\020\220\001\330\014\017\210q\220\010\230\t\240\021\240&\250\004\250C\250t\2603\260b\270\n\300!\330\014\r\330\014\033\2307\240!\2401\330\014\017\210w\220a\220q\330\014\016\210g\220Q\220a\340\010\r\210X\220\\\240\027\250""\001\250\021\330\010\014\210J\220a\220q\330\010\014\320\014\035\230Q\200A\330\010%\240T\250\027\260\006\260a\340\010\016\210c\220\023\220D\230\007\230t\2401\330\014\021\220\021\220,\230c\240\021\330\014\024\220L\240\003\2401\330\014\036\230i\240q\250\001\330\014\021\220\021\220!\330\014\031\230\021\230!\200\001\330\004\n\210+\220Q";
     PyObject *data = NULL;
     CYTHON_UNUSED_VAR(__Pyx_DecompressString);
     #endif
     PyObject **stringtab = __pyx_mstate->__pyx_string_tab;
     Py_ssize_t pos = 0;
-    for (int i = 0; i < 80; i++) {
+    for (int i = 0; i < 82; i++) {
       Py_ssize_t bytes_length = index[i].length;
       PyObject *string = PyUnicode_DecodeUTF8(bytes + pos, bytes_length, NULL);
-      if (likely(string) && i >= 16) PyUnicode_InternInPlace(&string);
+      if (likely(string) && i >= 14) PyUnicode_InternInPlace(&string);
       if (unlikely(!string)) {
         Py_XDECREF(data);
         __PYX_ERR(0, 1, __pyx_L1_error)
@@ -7537,7 +8043,7 @@ const char* const bytes = "Allocation of block object failedCould not allocate h
       stringtab[i] = string;
       pos += bytes_length;
     }
-    for (int i = 80; i < 89; i++) {
+    for (int i = 82; i < 92; i++) {
       Py_ssize_t bytes_length = index[i].length;
       PyObject *string = PyBytes_FromStringAndSize(bytes + pos, bytes_length);
       stringtab[i] = string;
@@ -7548,15 +8054,15 @@ const char* const bytes = "Allocation of block object failedCould not allocate h
       }
     }
     Py_XDECREF(data);
-    for (Py_ssize_t i = 0; i < 89; i++) {
+    for (Py_ssize_t i = 0; i < 92; i++) {
       if (unlikely(PyObject_Hash(stringtab[i]) == -1)) {
         __PYX_ERR(0, 1, __pyx_L1_error)
       }
     }
     #if CYTHON_IMMORTAL_CONSTANTS
     {
-      PyObject **table = stringtab + 80;
-      for (Py_ssize_t i=0; i<9; ++i) {
+      PyObject **table = stringtab + 82;
+      for (Py_ssize_t i=0; i<10; ++i) {
         #if CYTHON_COMPILING_IN_CPYTHON_FREETHREADING
         Py_SET_REFCNT(table[i], _Py_IMMORTAL_REFCNT_LOCAL);
         #else
@@ -7598,7 +8104,7 @@ typedef struct {
     unsigned int num_kwonly_args : 1;
     unsigned int nlocals : 3;
     unsigned int flags : 10;
-    unsigned int first_line : 8;
+    unsigned int first_line : 9;
 } __Pyx_PyCode_New_function_description;
 /* NewCodeObj.proto */
 static PyObject* __Pyx_PyCode_New(
@@ -7614,45 +8120,50 @@ static PyObject* __Pyx_PyCode_New(
 static int __Pyx_CreateCodeObjects(__pyx_mstatetype *__pyx_mstate) {
   PyObject* tuple_dedup_map = PyDict_New();
   if (unlikely(!tuple_dedup_map)) return -1;
+  {
+    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 2, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 203};
+    PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __pyx_mstate->__pyx_n_u_serialize_res};
+    __pyx_mstate_global->__pyx_codeobj_tab[0] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_bytes_serialize, __pyx_mstate->__pyx_kp_b_iso88591_A_D_2_Bm1_a, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[0])) goto bad;
+  }
   {
     const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 1, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 1};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self};
-    __pyx_mstate_global->__pyx_codeobj_tab[0] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_reduce_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[0])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[1] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_reduce_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[1])) goto bad;
   }
   {
     const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 2, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 3};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __pyx_mstate->__pyx_n_u_pyx_state};
-    __pyx_mstate_global->__pyx_codeobj_tab[1] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_setstate_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[1])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[2] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_setstate_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[2])) goto bad;
   }
   {
-    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 4, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 189};
+    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 4, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 256};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __pyx_mstate->__pyx_n_u_it, __pyx_mstate->__pyx_n_u_block, __pyx_mstate->__pyx_n_u_py_block};
-    __pyx_mstate_global->__pyx_codeobj_tab[2] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_print_key_value_pair, __pyx_mstate->__pyx_kp_b_iso88591_A_T_a_c_D_t1_c_L_1_iq, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[2])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[3] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_print_key_value_pair, __pyx_mstate->__pyx_kp_b_iso88591_A_T_a_c_D_t1_c_L_1_iq, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[3])) goto bad;
   }
   {
-    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 3, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 211};
+    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 3, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 278};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __pyx_mstate->__pyx_n_u_idx, __pyx_mstate->__pyx_n_u_block};
-    __pyx_mstate_global->__pyx_codeobj_tab[3] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_get_block, __pyx_mstate->__pyx_kp_b_iso88591_A_4r_3d_D_AQ_D_AQ_iq_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[3])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[4] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_get_block, __pyx_mstate->__pyx_kp_b_iso88591_A_4r_3d_D_AQ_D_AQ_iq_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[4])) goto bad;
   }
   {
-    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 2, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 223};
+    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 2, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 290};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __pyx_mstate->__pyx_n_u_block};
-    __pyx_mstate_global->__pyx_codeobj_tab[4] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_create_genesis_block, __pyx_mstate->__pyx_kp_b_iso88591_A_IQ_IQfD_4s_Ja_7_1_waq_gQa_X_Ja, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[4])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[5] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_create_genesis_block, __pyx_mstate->__pyx_kp_b_iso88591_A_IQ_q_Ct3b_7_1_waq_gQa_X_Jaq_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[5])) goto bad;
   }
   {
-    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 6, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 236};
+    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 6, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 303};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __pyx_mstate->__pyx_n_u_data, __pyx_mstate->__pyx_n_u_prev_block, __pyx_mstate->__pyx_n_u_prev_hash, __pyx_mstate->__pyx_n_u_new_idx, __pyx_mstate->__pyx_n_u_block};
-    __pyx_mstate_global->__pyx_codeobj_tab[5] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_new_block, __pyx_mstate->__pyx_kp_b_iso88591_A_4t1_aq_a_HBa_IQ_IQfD_4s_Ja_q_g, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[5])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[6] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_src_polluck_blockchain_placehold, __pyx_mstate->__pyx_n_u_new_block, __pyx_mstate->__pyx_kp_b_iso88591_A_4t1_aq_a_HBa_IQ_q_Ct3b_q_gQa_J, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[6])) goto bad;
   }
   {
     const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 1, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 1};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self};
-    __pyx_mstate_global->__pyx_codeobj_tab[6] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_reduce_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[6])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[7] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_reduce_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[7])) goto bad;
   }
   {
     const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 2, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 3};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __pyx_mstate->__pyx_n_u_pyx_state};
-    __pyx_mstate_global->__pyx_codeobj_tab[7] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_setstate_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[7])) goto bad;
+    __pyx_mstate_global->__pyx_codeobj_tab[8] = __Pyx_PyCode_New(descr, varnames, __pyx_mstate->__pyx_kp_u_stringsource, __pyx_mstate->__pyx_n_u_setstate_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[8])) goto bad;
   }
   Py_DECREF(tuple_dedup_map);
   return 0;
@@ -8984,114 +9495,6 @@ static void __Pyx_RaiseArgtupleInvalid(
                  (num_expected == 1) ? "" : "s", num_found);
 }
 
-/* RaiseException */
-static void __Pyx_Raise(PyObject *type, PyObject *value, PyObject *tb, PyObject *cause) {
-    PyObject* owned_instance = NULL;
-    if (tb == Py_None) {
-        tb = 0;
-    } else if (tb && !PyTraceBack_Check(tb)) {
-        PyErr_SetString(PyExc_TypeError,
-            "raise: arg 3 must be a traceback or None");
-        goto bad;
-    }
-    if (value == Py_None)
-        value = 0;
-    if (PyExceptionInstance_Check(type)) {
-        if (value) {
-            PyErr_SetString(PyExc_TypeError,
-                "instance exception may not have a separate value");
-            goto bad;
-        }
-        value = type;
-        type = (PyObject*) Py_TYPE(value);
-    } else if (PyExceptionClass_Check(type)) {
-        PyObject *instance_class = NULL;
-        if (value && PyExceptionInstance_Check(value)) {
-            instance_class = (PyObject*) Py_TYPE(value);
-            if (instance_class != type) {
-                int is_subclass = PyObject_IsSubclass(instance_class, type);
-                if (!is_subclass) {
-                    instance_class = NULL;
-                } else if (unlikely(is_subclass == -1)) {
-                    goto bad;
-                } else {
-                    type = instance_class;
-                }
-            }
-        }
-        if (!instance_class) {
-            PyObject *args;
-            if (!value)
-                args = PyTuple_New(0);
-            else if (PyTuple_Check(value)) {
-                Py_INCREF(value);
-                args = value;
-            } else
-                args = PyTuple_Pack(1, value);
-            if (!args)
-                goto bad;
-            owned_instance = PyObject_Call(type, args, NULL);
-            Py_DECREF(args);
-            if (!owned_instance)
-                goto bad;
-            value = owned_instance;
-            if (!PyExceptionInstance_Check(value)) {
-                PyErr_Format(PyExc_TypeError,
-                             "calling %R should have returned an instance of "
-                             "BaseException, not %R",
-                             type, Py_TYPE(value));
-                goto bad;
-            }
-        }
-    } else {
-        PyErr_SetString(PyExc_TypeError,
-            "raise: exception class must be a subclass of BaseException");
-        goto bad;
-    }
-    if (cause) {
-        PyObject *fixed_cause;
-        if (cause == Py_None) {
-            fixed_cause = NULL;
-        } else if (PyExceptionClass_Check(cause)) {
-            fixed_cause = PyObject_CallObject(cause, NULL);
-            if (fixed_cause == NULL)
-                goto bad;
-        } else if (PyExceptionInstance_Check(cause)) {
-            fixed_cause = cause;
-            Py_INCREF(fixed_cause);
-        } else {
-            PyErr_SetString(PyExc_TypeError,
-                            "exception causes must derive from "
-                            "BaseException");
-            goto bad;
-        }
-        PyException_SetCause(value, fixed_cause);
-    }
-    PyErr_SetObject(type, value);
-    if (tb) {
-#if PY_VERSION_HEX >= 0x030C00A6
-        PyException_SetTraceback(value, tb);
-#elif CYTHON_FAST_THREAD_STATE
-        PyThreadState *tstate = __Pyx_PyThreadState_Current;
-        PyObject* tmp_tb = tstate->curexc_traceback;
-        if (tb != tmp_tb) {
-            Py_INCREF(tb);
-            tstate->curexc_traceback = tb;
-            Py_XDECREF(tmp_tb);
-        }
-#else
-        PyObject *tmp_type, *tmp_value, *tmp_tb;
-        PyErr_Fetch(&tmp_type, &tmp_value, &tmp_tb);
-        Py_INCREF(tb);
-        PyErr_Restore(tmp_type, tmp_value, tb);
-        Py_XDECREF(tmp_tb);
-#endif
-    }
-bad:
-    Py_XDECREF(owned_instance);
-    return;
-}
-
 /* KeywordStringCheck */
 static int __Pyx_CheckKeywordStrings(
     const char* function_name,
@@ -9267,6 +9670,353 @@ static void __Pyx_RejectKeywords(const char* function_name, PyObject *kwds) {
     }
 }
 
+/* GetException */
+#if CYTHON_FAST_THREAD_STATE
+static int __Pyx__GetException(PyThreadState *tstate, PyObject **type, PyObject **value, PyObject **tb)
+#else
+static int __Pyx_GetException(PyObject **type, PyObject **value, PyObject **tb)
+#endif
+{
+    PyObject *local_type = NULL, *local_value, *local_tb = NULL;
+#if CYTHON_FAST_THREAD_STATE
+    PyObject *tmp_type, *tmp_value, *tmp_tb;
+  #if PY_VERSION_HEX >= 0x030C0000
+    local_value = tstate->current_exception;
+    tstate->current_exception = 0;
+  #else
+    local_type = tstate->curexc_type;
+    local_value = tstate->curexc_value;
+    local_tb = tstate->curexc_traceback;
+    tstate->curexc_type = 0;
+    tstate->curexc_value = 0;
+    tstate->curexc_traceback = 0;
+  #endif
+#elif __PYX_LIMITED_VERSION_HEX > 0x030C0000
+    local_value = PyErr_GetRaisedException();
+#else
+    PyErr_Fetch(&local_type, &local_value, &local_tb);
+#endif
+#if __PYX_LIMITED_VERSION_HEX > 0x030C0000
+    if (likely(local_value)) {
+        local_type = (PyObject*) Py_TYPE(local_value);
+        Py_INCREF(local_type);
+        local_tb = PyException_GetTraceback(local_value);
+    }
+#else
+    PyErr_NormalizeException(&local_type, &local_value, &local_tb);
+#if CYTHON_FAST_THREAD_STATE
+    if (unlikely(tstate->curexc_type))
+#else
+    if (unlikely(PyErr_Occurred()))
+#endif
+        goto bad;
+    if (local_tb) {
+        if (unlikely(PyException_SetTraceback(local_value, local_tb) < 0))
+            goto bad;
+    }
+#endif // __PYX_LIMITED_VERSION_HEX > 0x030C0000
+    Py_XINCREF(local_tb);
+    Py_XINCREF(local_type);
+    Py_XINCREF(local_value);
+    *type = local_type;
+    *value = local_value;
+    *tb = local_tb;
+#if CYTHON_FAST_THREAD_STATE
+    #if CYTHON_USE_EXC_INFO_STACK
+    {
+        _PyErr_StackItem *exc_info = tstate->exc_info;
+      #if PY_VERSION_HEX >= 0x030B00a4
+        tmp_value = exc_info->exc_value;
+        exc_info->exc_value = local_value;
+        tmp_type = NULL;
+        tmp_tb = NULL;
+        Py_XDECREF(local_type);
+        Py_XDECREF(local_tb);
+      #else
+        tmp_type = exc_info->exc_type;
+        tmp_value = exc_info->exc_value;
+        tmp_tb = exc_info->exc_traceback;
+        exc_info->exc_type = local_type;
+        exc_info->exc_value = local_value;
+        exc_info->exc_traceback = local_tb;
+      #endif
+    }
+    #else
+    tmp_type = tstate->exc_type;
+    tmp_value = tstate->exc_value;
+    tmp_tb = tstate->exc_traceback;
+    tstate->exc_type = local_type;
+    tstate->exc_value = local_value;
+    tstate->exc_traceback = local_tb;
+    #endif
+    Py_XDECREF(tmp_type);
+    Py_XDECREF(tmp_value);
+    Py_XDECREF(tmp_tb);
+#elif __PYX_LIMITED_VERSION_HEX >= 0x030b0000
+    PyErr_SetHandledException(local_value);
+    Py_XDECREF(local_value);
+    Py_XDECREF(local_type);
+    Py_XDECREF(local_tb);
+#else
+    PyErr_SetExcInfo(local_type, local_value, local_tb);
+#endif
+    return 0;
+#if __PYX_LIMITED_VERSION_HEX <= 0x030C0000
+bad:
+    *type = 0;
+    *value = 0;
+    *tb = 0;
+    Py_XDECREF(local_type);
+    Py_XDECREF(local_value);
+    Py_XDECREF(local_tb);
+    return -1;
+#endif
+}
+
+/* SwapException */
+#if CYTHON_FAST_THREAD_STATE
+static CYTHON_INLINE void __Pyx__ExceptionSwap(PyThreadState *tstate, PyObject **type, PyObject **value, PyObject **tb) {
+    PyObject *tmp_type, *tmp_value, *tmp_tb;
+  #if CYTHON_USE_EXC_INFO_STACK && PY_VERSION_HEX >= 0x030B00a4
+    _PyErr_StackItem *exc_info = tstate->exc_info;
+    tmp_value = exc_info->exc_value;
+    exc_info->exc_value = *value;
+    if (tmp_value == NULL || tmp_value == Py_None) {
+        Py_XDECREF(tmp_value);
+        tmp_value = NULL;
+        tmp_type = NULL;
+        tmp_tb = NULL;
+    } else {
+        tmp_type = (PyObject*) Py_TYPE(tmp_value);
+        Py_INCREF(tmp_type);
+        #if CYTHON_COMPILING_IN_CPYTHON
+        tmp_tb = ((PyBaseExceptionObject*) tmp_value)->traceback;
+        Py_XINCREF(tmp_tb);
+        #else
+        tmp_tb = PyException_GetTraceback(tmp_value);
+        #endif
+    }
+  #elif CYTHON_USE_EXC_INFO_STACK
+    _PyErr_StackItem *exc_info = tstate->exc_info;
+    tmp_type = exc_info->exc_type;
+    tmp_value = exc_info->exc_value;
+    tmp_tb = exc_info->exc_traceback;
+    exc_info->exc_type = *type;
+    exc_info->exc_value = *value;
+    exc_info->exc_traceback = *tb;
+  #else
+    tmp_type = tstate->exc_type;
+    tmp_value = tstate->exc_value;
+    tmp_tb = tstate->exc_traceback;
+    tstate->exc_type = *type;
+    tstate->exc_value = *value;
+    tstate->exc_traceback = *tb;
+  #endif
+    *type = tmp_type;
+    *value = tmp_value;
+    *tb = tmp_tb;
+}
+#else
+static CYTHON_INLINE void __Pyx_ExceptionSwap(PyObject **type, PyObject **value, PyObject **tb) {
+    PyObject *tmp_type, *tmp_value, *tmp_tb;
+    PyErr_GetExcInfo(&tmp_type, &tmp_value, &tmp_tb);
+    PyErr_SetExcInfo(*type, *value, *tb);
+    *type = tmp_type;
+    *value = tmp_value;
+    *tb = tmp_tb;
+}
+#endif
+
+/* GetTopmostException (used by SaveResetException) */
+#if CYTHON_USE_EXC_INFO_STACK && CYTHON_FAST_THREAD_STATE
+static _PyErr_StackItem *
+__Pyx_PyErr_GetTopmostException(PyThreadState *tstate)
+{
+    _PyErr_StackItem *exc_info = tstate->exc_info;
+    while ((exc_info->exc_value == NULL || exc_info->exc_value == Py_None) &&
+           exc_info->previous_item != NULL)
+    {
+        exc_info = exc_info->previous_item;
+    }
+    return exc_info;
+}
+#endif
+
+/* SaveResetException */
+#if CYTHON_FAST_THREAD_STATE
+static CYTHON_INLINE void __Pyx__ExceptionSave(PyThreadState *tstate, PyObject **type, PyObject **value, PyObject **tb) {
+  #if CYTHON_USE_EXC_INFO_STACK && PY_VERSION_HEX >= 0x030B00a4
+    _PyErr_StackItem *exc_info = __Pyx_PyErr_GetTopmostException(tstate);
+    PyObject *exc_value = exc_info->exc_value;
+    if (exc_value == NULL || exc_value == Py_None) {
+        *value = NULL;
+        *type = NULL;
+        *tb = NULL;
+    } else {
+        *value = exc_value;
+        Py_INCREF(*value);
+        *type = (PyObject*) Py_TYPE(exc_value);
+        Py_INCREF(*type);
+        *tb = PyException_GetTraceback(exc_value);
+    }
+  #elif CYTHON_USE_EXC_INFO_STACK
+    _PyErr_StackItem *exc_info = __Pyx_PyErr_GetTopmostException(tstate);
+    *type = exc_info->exc_type;
+    *value = exc_info->exc_value;
+    *tb = exc_info->exc_traceback;
+    Py_XINCREF(*type);
+    Py_XINCREF(*value);
+    Py_XINCREF(*tb);
+  #else
+    *type = tstate->exc_type;
+    *value = tstate->exc_value;
+    *tb = tstate->exc_traceback;
+    Py_XINCREF(*type);
+    Py_XINCREF(*value);
+    Py_XINCREF(*tb);
+  #endif
+}
+static CYTHON_INLINE void __Pyx__ExceptionReset(PyThreadState *tstate, PyObject *type, PyObject *value, PyObject *tb) {
+  #if CYTHON_USE_EXC_INFO_STACK && PY_VERSION_HEX >= 0x030B00a4
+    _PyErr_StackItem *exc_info = tstate->exc_info;
+    PyObject *tmp_value = exc_info->exc_value;
+    exc_info->exc_value = value;
+    Py_XDECREF(tmp_value);
+    Py_XDECREF(type);
+    Py_XDECREF(tb);
+  #else
+    PyObject *tmp_type, *tmp_value, *tmp_tb;
+    #if CYTHON_USE_EXC_INFO_STACK
+    _PyErr_StackItem *exc_info = tstate->exc_info;
+    tmp_type = exc_info->exc_type;
+    tmp_value = exc_info->exc_value;
+    tmp_tb = exc_info->exc_traceback;
+    exc_info->exc_type = type;
+    exc_info->exc_value = value;
+    exc_info->exc_traceback = tb;
+    #else
+    tmp_type = tstate->exc_type;
+    tmp_value = tstate->exc_value;
+    tmp_tb = tstate->exc_traceback;
+    tstate->exc_type = type;
+    tstate->exc_value = value;
+    tstate->exc_traceback = tb;
+    #endif
+    Py_XDECREF(tmp_type);
+    Py_XDECREF(tmp_value);
+    Py_XDECREF(tmp_tb);
+  #endif
+}
+#endif
+
+/* RaiseException */
+static void __Pyx_Raise(PyObject *type, PyObject *value, PyObject *tb, PyObject *cause) {
+    PyObject* owned_instance = NULL;
+    if (tb == Py_None) {
+        tb = 0;
+    } else if (tb && !PyTraceBack_Check(tb)) {
+        PyErr_SetString(PyExc_TypeError,
+            "raise: arg 3 must be a traceback or None");
+        goto bad;
+    }
+    if (value == Py_None)
+        value = 0;
+    if (PyExceptionInstance_Check(type)) {
+        if (value) {
+            PyErr_SetString(PyExc_TypeError,
+                "instance exception may not have a separate value");
+            goto bad;
+        }
+        value = type;
+        type = (PyObject*) Py_TYPE(value);
+    } else if (PyExceptionClass_Check(type)) {
+        PyObject *instance_class = NULL;
+        if (value && PyExceptionInstance_Check(value)) {
+            instance_class = (PyObject*) Py_TYPE(value);
+            if (instance_class != type) {
+                int is_subclass = PyObject_IsSubclass(instance_class, type);
+                if (!is_subclass) {
+                    instance_class = NULL;
+                } else if (unlikely(is_subclass == -1)) {
+                    goto bad;
+                } else {
+                    type = instance_class;
+                }
+            }
+        }
+        if (!instance_class) {
+            PyObject *args;
+            if (!value)
+                args = PyTuple_New(0);
+            else if (PyTuple_Check(value)) {
+                Py_INCREF(value);
+                args = value;
+            } else
+                args = PyTuple_Pack(1, value);
+            if (!args)
+                goto bad;
+            owned_instance = PyObject_Call(type, args, NULL);
+            Py_DECREF(args);
+            if (!owned_instance)
+                goto bad;
+            value = owned_instance;
+            if (!PyExceptionInstance_Check(value)) {
+                PyErr_Format(PyExc_TypeError,
+                             "calling %R should have returned an instance of "
+                             "BaseException, not %R",
+                             type, Py_TYPE(value));
+                goto bad;
+            }
+        }
+    } else {
+        PyErr_SetString(PyExc_TypeError,
+            "raise: exception class must be a subclass of BaseException");
+        goto bad;
+    }
+    if (cause) {
+        PyObject *fixed_cause;
+        if (cause == Py_None) {
+            fixed_cause = NULL;
+        } else if (PyExceptionClass_Check(cause)) {
+            fixed_cause = PyObject_CallObject(cause, NULL);
+            if (fixed_cause == NULL)
+                goto bad;
+        } else if (PyExceptionInstance_Check(cause)) {
+            fixed_cause = cause;
+            Py_INCREF(fixed_cause);
+        } else {
+            PyErr_SetString(PyExc_TypeError,
+                            "exception causes must derive from "
+                            "BaseException");
+            goto bad;
+        }
+        PyException_SetCause(value, fixed_cause);
+    }
+    PyErr_SetObject(type, value);
+    if (tb) {
+#if PY_VERSION_HEX >= 0x030C00A6
+        PyException_SetTraceback(value, tb);
+#elif CYTHON_FAST_THREAD_STATE
+        PyThreadState *tstate = __Pyx_PyThreadState_Current;
+        PyObject* tmp_tb = tstate->curexc_traceback;
+        if (tb != tmp_tb) {
+            Py_INCREF(tb);
+            tstate->curexc_traceback = tb;
+            Py_XDECREF(tmp_tb);
+        }
+#else
+        PyObject *tmp_type, *tmp_value, *tmp_tb;
+        PyErr_Fetch(&tmp_type, &tmp_value, &tmp_tb);
+        Py_INCREF(tb);
+        PyErr_Restore(tmp_type, tmp_value, tb);
+        Py_XDECREF(tmp_tb);
+#endif
+    }
+bad:
+    Py_XDECREF(owned_instance);
+    return;
+}
+
 /* AllocateExtensionType */
 static PyObject *__Pyx_AllocateExtensionType(PyTypeObject *t, int is_final) {
     if (is_final || likely(!__Pyx_PyType_HasFeature(t, Py_TPFLAGS_IS_ABSTRACT))) {
@@ -11829,6 +12579,107 @@ bad:
         return (target_type) value;\
     }
 
+/* PyObjectVectorCallKwBuilder (used by CIntToPy) */
+#if CYTHON_VECTORCALL
+static int __Pyx_VectorcallBuilder_AddArg(PyObject *key, PyObject *value, PyObject *builder, PyObject **args, int n) {
+    (void)__Pyx_PyObject_FastCallDict;
+    if (__Pyx_PyTuple_SET_ITEM(builder, n, key) != (0)) return -1;
+    Py_INCREF(key);
+    args[n] = value;
+    return 0;
+}
+CYTHON_UNUSED static int __Pyx_VectorcallBuilder_AddArg_Check(PyObject *key, PyObject *value, PyObject *builder, PyObject **args, int n) {
+    (void)__Pyx_VectorcallBuilder_AddArgStr;
+    if (unlikely(!PyUnicode_Check(key))) {
+        PyErr_SetString(PyExc_TypeError, "keywords must be strings");
+        return -1;
+    }
+    return __Pyx_VectorcallBuilder_AddArg(key, value, builder, args, n);
+}
+static int __Pyx_VectorcallBuilder_AddArgStr(const char *key, PyObject *value, PyObject *builder, PyObject **args, int n) {
+    PyObject *pyKey = PyUnicode_FromString(key);
+    if (!pyKey) return -1;
+    return __Pyx_VectorcallBuilder_AddArg(pyKey, value, builder, args, n);
+}
+#else // CYTHON_VECTORCALL
+CYTHON_UNUSED static int __Pyx_VectorcallBuilder_AddArg_Check(PyObject *key, PyObject *value, PyObject *builder, CYTHON_UNUSED PyObject **args, CYTHON_UNUSED int n) {
+    if (unlikely(!PyUnicode_Check(key))) {
+        PyErr_SetString(PyExc_TypeError, "keywords must be strings");
+        return -1;
+    }
+    return PyDict_SetItem(builder, key, value);
+}
+#endif
+
+/* CIntToPy */
+static CYTHON_INLINE PyObject* __Pyx_PyLong_From_uint64_t(uint64_t value) {
+#ifdef __Pyx_HAS_GCC_DIAGNOSTIC
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wconversion"
+#endif
+    const uint64_t neg_one = (uint64_t) -1, const_zero = (uint64_t) 0;
+#ifdef __Pyx_HAS_GCC_DIAGNOSTIC
+#pragma GCC diagnostic pop
+#endif
+    const int is_unsigned = neg_one > const_zero;
+    if (is_unsigned) {
+        if (sizeof(uint64_t) < sizeof(long)) {
+            return PyLong_FromLong((long) value);
+        } else if (sizeof(uint64_t) <= sizeof(unsigned long)) {
+            return PyLong_FromUnsignedLong((unsigned long) value);
+#if !CYTHON_COMPILING_IN_PYPY
+        } else if (sizeof(uint64_t) <= sizeof(unsigned PY_LONG_LONG)) {
+            return PyLong_FromUnsignedLongLong((unsigned PY_LONG_LONG) value);
+#endif
+        }
+    } else {
+        if (sizeof(uint64_t) <= sizeof(long)) {
+            return PyLong_FromLong((long) value);
+        } else if (sizeof(uint64_t) <= sizeof(PY_LONG_LONG)) {
+            return PyLong_FromLongLong((PY_LONG_LONG) value);
+        }
+    }
+    {
+        unsigned char *bytes = (unsigned char *)&value;
+#if !CYTHON_COMPILING_IN_LIMITED_API && PY_VERSION_HEX >= 0x030d00A4
+        if (is_unsigned) {
+            return PyLong_FromUnsignedNativeBytes(bytes, sizeof(value), -1);
+        } else {
+            return PyLong_FromNativeBytes(bytes, sizeof(value), -1);
+        }
+#elif !CYTHON_COMPILING_IN_LIMITED_API && PY_VERSION_HEX < 0x030d0000
+        int one = 1; int little = (int)*(unsigned char *)&one;
+        return _PyLong_FromByteArray(bytes, sizeof(uint64_t),
+                                     little, !is_unsigned);
+#else
+        int one = 1; int little = (int)*(unsigned char *)&one;
+        PyObject *from_bytes, *result = NULL, *kwds = NULL;
+        PyObject *py_bytes = NULL, *order_str = NULL;
+        from_bytes = PyObject_GetAttrString((PyObject*)&PyLong_Type, "from_bytes");
+        if (!from_bytes) return NULL;
+        py_bytes = PyBytes_FromStringAndSize((char*)bytes, sizeof(uint64_t));
+        if (!py_bytes) goto limited_bad;
+        order_str = PyUnicode_FromString(little ? "little" : "big");
+        if (!order_str) goto limited_bad;
+        {
+            PyObject *args[3+(CYTHON_VECTORCALL ? 1 : 0)] = { NULL, py_bytes, order_str };
+            if (!is_unsigned) {
+                kwds = __Pyx_MakeVectorcallBuilderKwds(1);
+                if (!kwds) goto limited_bad;
+                if (__Pyx_VectorcallBuilder_AddArgStr("signed", __Pyx_NewRef(Py_True), kwds, args+3, 0) < 0) goto limited_bad;
+            }
+            result = __Pyx_Object_Vectorcall_CallFromBuilder(from_bytes, args+1, 2 | __Pyx_PY_VECTORCALL_ARGUMENTS_OFFSET, kwds);
+        }
+        limited_bad:
+        Py_XDECREF(kwds);
+        Py_XDECREF(order_str);
+        Py_XDECREF(py_bytes);
+        Py_XDECREF(from_bytes);
+        return result;
+#endif
+    }
+}
+
 /* CIntFromPy */
 static CYTHON_INLINE uint64_t __Pyx_PyLong_As_uint64_t(PyObject *x) {
 #ifdef __Pyx_HAS_GCC_DIAGNOSTIC
@@ -12079,107 +12930,6 @@ raise_neg_overflow:
     return (uint64_t) -1;
 }
 
-/* PyObjectVectorCallKwBuilder (used by CIntToPy) */
-#if CYTHON_VECTORCALL
-static int __Pyx_VectorcallBuilder_AddArg(PyObject *key, PyObject *value, PyObject *builder, PyObject **args, int n) {
-    (void)__Pyx_PyObject_FastCallDict;
-    if (__Pyx_PyTuple_SET_ITEM(builder, n, key) != (0)) return -1;
-    Py_INCREF(key);
-    args[n] = value;
-    return 0;
-}
-CYTHON_UNUSED static int __Pyx_VectorcallBuilder_AddArg_Check(PyObject *key, PyObject *value, PyObject *builder, PyObject **args, int n) {
-    (void)__Pyx_VectorcallBuilder_AddArgStr;
-    if (unlikely(!PyUnicode_Check(key))) {
-        PyErr_SetString(PyExc_TypeError, "keywords must be strings");
-        return -1;
-    }
-    return __Pyx_VectorcallBuilder_AddArg(key, value, builder, args, n);
-}
-static int __Pyx_VectorcallBuilder_AddArgStr(const char *key, PyObject *value, PyObject *builder, PyObject **args, int n) {
-    PyObject *pyKey = PyUnicode_FromString(key);
-    if (!pyKey) return -1;
-    return __Pyx_VectorcallBuilder_AddArg(pyKey, value, builder, args, n);
-}
-#else // CYTHON_VECTORCALL
-CYTHON_UNUSED static int __Pyx_VectorcallBuilder_AddArg_Check(PyObject *key, PyObject *value, PyObject *builder, CYTHON_UNUSED PyObject **args, CYTHON_UNUSED int n) {
-    if (unlikely(!PyUnicode_Check(key))) {
-        PyErr_SetString(PyExc_TypeError, "keywords must be strings");
-        return -1;
-    }
-    return PyDict_SetItem(builder, key, value);
-}
-#endif
-
-/* CIntToPy */
-static CYTHON_INLINE PyObject* __Pyx_PyLong_From_uint64_t(uint64_t value) {
-#ifdef __Pyx_HAS_GCC_DIAGNOSTIC
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wconversion"
-#endif
-    const uint64_t neg_one = (uint64_t) -1, const_zero = (uint64_t) 0;
-#ifdef __Pyx_HAS_GCC_DIAGNOSTIC
-#pragma GCC diagnostic pop
-#endif
-    const int is_unsigned = neg_one > const_zero;
-    if (is_unsigned) {
-        if (sizeof(uint64_t) < sizeof(long)) {
-            return PyLong_FromLong((long) value);
-        } else if (sizeof(uint64_t) <= sizeof(unsigned long)) {
-            return PyLong_FromUnsignedLong((unsigned long) value);
-#if !CYTHON_COMPILING_IN_PYPY
-        } else if (sizeof(uint64_t) <= sizeof(unsigned PY_LONG_LONG)) {
-            return PyLong_FromUnsignedLongLong((unsigned PY_LONG_LONG) value);
-#endif
-        }
-    } else {
-        if (sizeof(uint64_t) <= sizeof(long)) {
-            return PyLong_FromLong((long) value);
-        } else if (sizeof(uint64_t) <= sizeof(PY_LONG_LONG)) {
-            return PyLong_FromLongLong((PY_LONG_LONG) value);
-        }
-    }
-    {
-        unsigned char *bytes = (unsigned char *)&value;
-#if !CYTHON_COMPILING_IN_LIMITED_API && PY_VERSION_HEX >= 0x030d00A4
-        if (is_unsigned) {
-            return PyLong_FromUnsignedNativeBytes(bytes, sizeof(value), -1);
-        } else {
-            return PyLong_FromNativeBytes(bytes, sizeof(value), -1);
-        }
-#elif !CYTHON_COMPILING_IN_LIMITED_API && PY_VERSION_HEX < 0x030d0000
-        int one = 1; int little = (int)*(unsigned char *)&one;
-        return _PyLong_FromByteArray(bytes, sizeof(uint64_t),
-                                     little, !is_unsigned);
-#else
-        int one = 1; int little = (int)*(unsigned char *)&one;
-        PyObject *from_bytes, *result = NULL, *kwds = NULL;
-        PyObject *py_bytes = NULL, *order_str = NULL;
-        from_bytes = PyObject_GetAttrString((PyObject*)&PyLong_Type, "from_bytes");
-        if (!from_bytes) return NULL;
-        py_bytes = PyBytes_FromStringAndSize((char*)bytes, sizeof(uint64_t));
-        if (!py_bytes) goto limited_bad;
-        order_str = PyUnicode_FromString(little ? "little" : "big");
-        if (!order_str) goto limited_bad;
-        {
-            PyObject *args[3+(CYTHON_VECTORCALL ? 1 : 0)] = { NULL, py_bytes, order_str };
-            if (!is_unsigned) {
-                kwds = __Pyx_MakeVectorcallBuilderKwds(1);
-                if (!kwds) goto limited_bad;
-                if (__Pyx_VectorcallBuilder_AddArgStr("signed", __Pyx_NewRef(Py_True), kwds, args+3, 0) < 0) goto limited_bad;
-            }
-            result = __Pyx_Object_Vectorcall_CallFromBuilder(from_bytes, args+1, 2 | __Pyx_PY_VECTORCALL_ARGUMENTS_OFFSET, kwds);
-        }
-        limited_bad:
-        Py_XDECREF(kwds);
-        Py_XDECREF(order_str);
-        Py_XDECREF(py_bytes);
-        Py_XDECREF(from_bytes);
-        return result;
-#endif
-    }
-}
-
 /* FormatTypeName */
 #if CYTHON_COMPILING_IN_LIMITED_API && __PYX_LIMITED_VERSION_HEX < 0x030d0000
 static __Pyx_TypeName
diff --git a/src/polluck_blockchain/placeholder_native.pyx b/src/polluck_blockchain/placeholder_native.pyx
index f6ec72a..f0a2ecb 100644
--- a/src/polluck_blockchain/placeholder_native.pyx
+++ b/src/polluck_blockchain/placeholder_native.pyx
@@ -17,18 +17,40 @@ from polluck_blockchain.block cimport Block
 from libcpp.unordered_map cimport unordered_map
 from libcpp.string cimport string
 from libc.stdint cimport uint64_t
+from libc.stdlib cimport malloc, free
+from libc.string cimport memcpy
 from cython.operator import postincrement, dereference
 
+
 ctypedef unsigned long ULong
 ctypedef unordered_map[uint64_t, Block*] BcHashmap
 
-cdef timestamp_to_datetime(double ts):
-    return datetime.datetime.fromtimestamp(ts, dopt_basics.datetime.TIMEZONE_UTC)
+cdef timestamp_to_datetime(uint64_t ts):
+    return datetime.datetime.fromtimestamp(float(ts), dopt_basics.datetime.TIMEZONE_UTC)
 
 
-cdef float_to_bytes(double num):
-    return struct.pack(">d", num)
+# cdef float_to_bytes(double num):
+#     return struct.pack(">d", num)
 
+cdef int serialize_uint32(unsigned char* out, unsigned int v) except -1 nogil:
+    out[0] = (v >> 24) & 0xFF
+    out[1] = (v >> 16) & 0xFF
+    out[2] = (v >> 8)  & 0xFF
+    out[3] = v & 0xFF
+
+cdef int serialize_uint64(unsigned char* out, unsigned long long v) except -1 nogil:
+    out[0] = (v >> 56) & 0xFF
+    out[1] = (v >> 48) & 0xFF
+    out[2] = (v >> 40) & 0xFF
+    out[3] = (v >> 32) & 0xFF
+    out[4] = (v >> 24) & 0xFF
+    out[5] = (v >> 16) & 0xFF
+    out[6] = (v >> 8)  & 0xFF
+    out[7] = v & 0xFF
+
+cdef struct SerializeResult:
+    unsigned char *ptr
+    size_t size
 
 cdef class PyBlock:
     cdef:
@@ -52,26 +74,19 @@ cdef class PyBlock:
         if not from_ptr:
             self.BlockC = new Block(
                 index,
-                datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp(),
+                int(datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp()),
                 nonce,
                 data.encode("UTF-8"),
                 previous_hash.encode("UTF-8"),
                 "".encode("UTF-8"),
             )
             if self.BlockC == NULL:
-                raise MemoryError("Allocation of block object failed")
+                raise MemoryError()
 
             self.ptr_owner = True
 
     def __init__(self, *args, **kwargs):
         pass
-        # self._index = index
-        # # self._timestamp = dopt_basics.datetime.current_time_tz().timestamp()
-        # self._timestamp = datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp()
-        # self._data = data.encode("UTF-8")
-        # self._prev_hash = previous_hash.encode("UTF-8")
-        # self._nonce = nonce
-        # self._hash = "".encode("UTF-8")
     
     def __dealloc__(self):
         if self.BlockC is not NULL and self.ptr_owner is True:
@@ -144,6 +159,58 @@ cdef class PyBlock:
     def hash(self):
         return self.BlockC.hash.decode("UTF-8")
 
+    cdef SerializeResult bytes_serialize_c(self):
+        cdef:
+            size_t total_len
+            unsigned char* buf
+            size_t pos = 0
+        
+        # index (8), timestamp (8), nonce (8), data, prev_hash
+        total_len = (
+            <size_t>(8 * 3) +
+            self.BlockC.data.size() + 
+            self.BlockC.prev_hash.size()
+        )
+        buf = <unsigned char*>malloc(total_len * sizeof(unsigned char))
+
+        if buf == NULL:
+            raise MemoryError()
+        
+        serialize_uint64(buf + pos, self.BlockC.index)
+        pos += 8
+        serialize_uint64(buf + pos, self.BlockC.timestamp)
+        pos += 8
+        serialize_uint64(buf + pos, self.BlockC.nonce)
+        pos += 8
+        # Copy data
+        memcpy(
+            buf + pos,
+            self.BlockC.data.c_str(),
+            self.BlockC.data.size(),
+        )
+        pos += self.BlockC.data.size()
+        # Copy prev_hash
+        memcpy(
+            buf + pos,
+            self.BlockC.prev_hash.c_str(),
+            self.BlockC.prev_hash.size(),
+        )
+        pos += self.BlockC.prev_hash.size()
+
+        return SerializeResult(buf, total_len)
+
+    def bytes_serialize(self):
+        cdef SerializeResult serialize_res
+        try:
+            serialize_res = self.bytes_serialize_c()
+            return serialize_res.ptr[:serialize_res.size]
+        finally:
+            free(serialize_res.ptr)
+
+
+
+
+
     # @hash.setter
     # def hash(self, value):
     #     if not isinstance(value, str):
@@ -222,7 +289,7 @@ cdef class Blockchain:
     def create_genesis_block(self):
         cdef Block *block = new Block(
             self._index,
-            datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp(),
+            int(datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp()),
             0,
             "Genesis Block".encode("UTF-8"),
             "0".encode("UTF-8"),
@@ -242,7 +309,7 @@ cdef class Blockchain:
 
         cdef Block *block = new Block(
             new_idx,
-            datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp(),
+            int(datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp()),
             0,
             data.encode("UTF-8"),
             prev_hash,