From 61753f03d81c25283b29ab21766a256b488cd616 Mon Sep 17 00:00:00 2001
From: foefl <f.foerster@d-opt.com>
Date: Fri, 12 Dec 2025 08:24:15 +0100
Subject: [PATCH] prepare hashing

---
 src/polluck_blockchain/placeholder_native.cpp | 1460 +++++++++++------
 src/polluck_blockchain/placeholder_native.pyx |   29 +-
 2 files changed, 1025 insertions(+), 464 deletions(-)

diff --git a/src/polluck_blockchain/placeholder_native.cpp b/src/polluck_blockchain/placeholder_native.cpp
index ee34eed..271d6ec 100644
--- a/src/polluck_blockchain/placeholder_native.cpp
+++ b/src/polluck_blockchain/placeholder_native.cpp
@@ -1553,8 +1553,8 @@ static const char* const __pyx_f[] = {
 
 /* #### Code section: numeric_typedefs ### */
 
-/* "polluck_blockchain/placeholder_native.pyx":21
- * from libc.stdint cimport uint64_t
+/* "polluck_blockchain/placeholder_native.pyx":22
+ * from cython.operator import postincrement, dereference
  * 
  * ctypedef unsigned long ULong             # <<<<<<<<<<<<<<
  * ctypedef unordered_map[uint64_t, Block*] BcHashmap
@@ -1569,7 +1569,7 @@ struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock;
 struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain;
 struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_ptr;
 
-/* "polluck_blockchain/placeholder_native.pyx":22
+/* "polluck_blockchain/placeholder_native.pyx":23
  * 
  * ctypedef unsigned long ULong
  * ctypedef unordered_map[uint64_t, Block*] BcHashmap             # <<<<<<<<<<<<<<
@@ -1578,7 +1578,7 @@ struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_pt
 */
 typedef std::unordered_map<uint64_t,::Block *>  __pyx_t_18polluck_blockchain_18placeholder_native_BcHashmap;
 
-/* "polluck_blockchain/placeholder_native.pyx":81
+/* "polluck_blockchain/placeholder_native.pyx":82
  * 
  *     @staticmethod
  *     cdef PyBlock from_ptr(Block *block, bint owner=False):             # <<<<<<<<<<<<<<
@@ -1590,7 +1590,7 @@ struct __pyx_opt_args_18polluck_blockchain_18placeholder_native_7PyBlock_from_pt
   int owner;
 };
 
-/* "polluck_blockchain/placeholder_native.pyx":32
+/* "polluck_blockchain/placeholder_native.pyx":33
  * 
  * 
  * cdef class PyBlock:             # <<<<<<<<<<<<<<
@@ -1605,7 +1605,7 @@ struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock {
 };
 
 
-/* "polluck_blockchain/placeholder_native.pyx":150
+/* "polluck_blockchain/placeholder_native.pyx":157
  * 
  * 
  * cdef class Blockchain:             # <<<<<<<<<<<<<<
@@ -1623,7 +1623,7 @@ struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain {
 
 
 
-/* "polluck_blockchain/placeholder_native.pyx":32
+/* "polluck_blockchain/placeholder_native.pyx":33
  * 
  * 
  * cdef class PyBlock:             # <<<<<<<<<<<<<<
@@ -1637,7 +1637,7 @@ struct __pyx_vtabstruct_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":150
+/* "polluck_blockchain/placeholder_native.pyx":157
  * 
  * 
  * cdef class Blockchain:             # <<<<<<<<<<<<<<
@@ -1787,7 +1787,7 @@ static CYTHON_INLINE PyObject* __Pyx_PyObject_GetAttrStr(PyObject* obj, PyObject
 /* PyObjectGetAttrStrNoError.proto (used by GetBuiltinName) */
 static CYTHON_INLINE PyObject* __Pyx_PyObject_GetAttrStrNoError(PyObject* obj, PyObject* attr_name);
 
-/* GetBuiltinName.proto (used by GetModuleGlobalName) */
+/* GetBuiltinName.proto */
 static PyObject *__Pyx_GetBuiltinName(PyObject *name);
 
 /* PyDictVersioning.proto (used by GetModuleGlobalName) */
@@ -2046,6 +2046,27 @@ static void __Pyx_Raise(PyObject *type, PyObject *value, PyObject *tb, PyObject
 /* KeywordStringCheck.proto */
 static CYTHON_INLINE int __Pyx_CheckKeywordStrings(const char* function_name, PyObject *kw);
 
+/* PyObjectFormatSimple.proto */
+#if CYTHON_COMPILING_IN_PYPY
+    #define __Pyx_PyObject_FormatSimple(s, f) (\
+        likely(PyUnicode_CheckExact(s)) ? (Py_INCREF(s), s) :\
+        PyObject_Format(s, f))
+#elif CYTHON_USE_TYPE_SLOTS
+    #define __Pyx_PyObject_FormatSimple(s, f) (\
+        likely(PyUnicode_CheckExact(s)) ? (Py_INCREF(s), s) :\
+        likely(PyLong_CheckExact(s)) ? PyLong_Type.tp_repr(s) :\
+        likely(PyFloat_CheckExact(s)) ? PyFloat_Type.tp_repr(s) :\
+        PyObject_Format(s, f))
+#else
+    #define __Pyx_PyObject_FormatSimple(s, f) (\
+        likely(PyUnicode_CheckExact(s)) ? (Py_INCREF(s), s) :\
+        PyObject_Format(s, f))
+#endif
+
+/* JoinPyUnicode.export */
+static PyObject* __Pyx_PyUnicode_Join(PyObject** values, Py_ssize_t value_count, Py_ssize_t result_ulength,
+                                      Py_UCS4 max_char);
+
 /* IncludeCppStringH.proto (used by decode_cpp_string) */
 #include <string>
 
@@ -2087,9 +2108,6 @@ static void __Pyx_RejectKeywords(const char* function_name, PyObject *kwds);
 /* PyIndexError_Check.proto */
 #define __Pyx_PyExc_IndexError_Check(obj)  __Pyx_TypeCheck(obj, PyExc_IndexError)
 
-/* PyRuntimeError_Check.proto */
-#define __Pyx_PyExc_RuntimeError_Check(obj)  __Pyx_TypeCheck(obj, PyExc_RuntimeError)
-
 /* MoveIfSupported.proto */
 #if CYTHON_USE_CPP_STD_MOVE
   #include <utility>
@@ -2098,6 +2116,9 @@ static void __Pyx_RejectKeywords(const char* function_name, PyObject *kwds);
   #define __PYX_STD_MOVE_IF_SUPPORTED(x) x
 #endif
 
+/* PyRuntimeError_Check.proto */
+#define __Pyx_PyExc_RuntimeError_Check(obj)  __Pyx_TypeCheck(obj, PyExc_RuntimeError)
+
 /* AllocateExtensionType.proto */
 static PyObject *__Pyx_AllocateExtensionType(PyTypeObject *t, int is_final);
 
@@ -2547,30 +2568,34 @@ int __pyx_module_is_main_polluck_blockchain__placeholder_native = 0;
 
 /* Implementation of "polluck_blockchain.placeholder_native" */
 /* #### Code section: global_var ### */
+static PyObject *__pyx_builtin_print;
 /* #### Code section: string_decls ### */
 /* #### Code section: decls ### */
 static int __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock___cinit__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self, PyObject *__pyx_v_index, PyObject *__pyx_v_nonce, PyObject *__pyx_v_data, PyObject *__pyx_v_previous_hash, PyObject *__pyx_v_from_ptr); /* proto */
 static int __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_2__init__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self, CYTHON_UNUSED PyObject *__pyx_v_args, CYTHON_UNUSED PyObject *__pyx_v_kwargs); /* proto */
 static void __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4__dealloc__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_6__repr__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_8__str__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_5index___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_9timestamp___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4data___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self); /* proto */
 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_6__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_8__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_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 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 */
 static Py_ssize_t __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_6__len__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_8print_key_value_pair(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_12genesis_done___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
 static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_5index___get__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_8get_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, PyObject *__pyx_v_idx); /* proto */
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_10create_genesis_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_12new_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, PyObject *__pyx_v_data); /* proto */
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_14__reduce_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_16__setstate_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, CYTHON_UNUSED PyObject *__pyx_v___pyx_state); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_10get_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, PyObject *__pyx_v_idx); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_12create_genesis_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_14new_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, PyObject *__pyx_v_data); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_16__reduce_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self); /* proto */
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_18__setstate_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self, CYTHON_UNUSED PyObject *__pyx_v___pyx_state); /* proto */
 static PyObject *__pyx_tp_new_18polluck_blockchain_18placeholder_native_PyBlock(PyTypeObject *t, PyObject *a, PyObject *k); /*proto*/
 static PyObject *__pyx_tp_new_18polluck_blockchain_18placeholder_native_Blockchain(PyTypeObject *t, PyObject *a, PyObject *k); /*proto*/
 /* #### Code section: late_includes ### */
@@ -2601,8 +2626,8 @@ typedef struct {
   __Pyx_CachedCFunction __pyx_umethod_PyDict_Type_pop;
   __Pyx_CachedCFunction __pyx_umethod_PyDict_Type_values;
   PyObject *__pyx_tuple[1];
-  PyObject *__pyx_codeobj_tab[7];
-  PyObject *__pyx_string_tab[80];
+  PyObject *__pyx_codeobj_tab[8];
+  PyObject *__pyx_string_tab[89];
   PyObject *__pyx_number_tab[4];
 /* #### Code section: module_state_contents ### */
 /* CommonTypesMetaclass.module_state_decls */
@@ -2648,82 +2673,91 @@ static __pyx_mstatetype * const __pyx_mstate_global = &__pyx_mstate_global_stati
 #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_UTF_8 __pyx_string_tab[4]
-#define __pyx_kp_u__2 __pyx_string_tab[5]
-#define __pyx_kp_u_d __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_PyBlock __pyx_string_tab[20]
-#define __pyx_n_u_PyBlock___reduce_cython __pyx_string_tab[21]
-#define __pyx_n_u_PyBlock___setstate_cython __pyx_string_tab[22]
-#define __pyx_n_u_Pyx_PyDict_NextRef __pyx_string_tab[23]
-#define __pyx_n_u_TIMEZONE_UTC __pyx_string_tab[24]
-#define __pyx_n_u_asyncio_coroutines __pyx_string_tab[25]
-#define __pyx_n_u_block __pyx_string_tab[26]
-#define __pyx_n_u_cline_in_traceback __pyx_string_tab[27]
-#define __pyx_n_u_create_genesis_block __pyx_string_tab[28]
-#define __pyx_n_u_data __pyx_string_tab[29]
-#define __pyx_n_u_datetime __pyx_string_tab[30]
-#define __pyx_n_u_dopt_basics __pyx_string_tab[31]
-#define __pyx_n_u_dopt_basics_datetime __pyx_string_tab[32]
-#define __pyx_n_u_encode __pyx_string_tab[33]
-#define __pyx_n_u_from_ptr __pyx_string_tab[34]
-#define __pyx_n_u_fromtimestamp __pyx_string_tab[35]
-#define __pyx_n_u_func __pyx_string_tab[36]
-#define __pyx_n_u_get_block __pyx_string_tab[37]
-#define __pyx_n_u_getstate __pyx_string_tab[38]
-#define __pyx_n_u_hashlib __pyx_string_tab[39]
-#define __pyx_n_u_idx __pyx_string_tab[40]
-#define __pyx_n_u_index __pyx_string_tab[41]
-#define __pyx_n_u_is_coroutine __pyx_string_tab[42]
-#define __pyx_n_u_items __pyx_string_tab[43]
-#define __pyx_n_u_main __pyx_string_tab[44]
-#define __pyx_n_u_module __pyx_string_tab[45]
-#define __pyx_n_u_name __pyx_string_tab[46]
-#define __pyx_n_u_new_block __pyx_string_tab[47]
-#define __pyx_n_u_new_idx __pyx_string_tab[48]
-#define __pyx_n_u_nonce __pyx_string_tab[49]
-#define __pyx_n_u_pack __pyx_string_tab[50]
-#define __pyx_n_u_polluck_blockchain_placeholder_n __pyx_string_tab[51]
-#define __pyx_n_u_pop __pyx_string_tab[52]
-#define __pyx_n_u_prev_block __pyx_string_tab[53]
-#define __pyx_n_u_prev_hash __pyx_string_tab[54]
-#define __pyx_n_u_previous_hash __pyx_string_tab[55]
-#define __pyx_n_u_pyx_state __pyx_string_tab[56]
-#define __pyx_n_u_pyx_vtable __pyx_string_tab[57]
-#define __pyx_n_u_qualname __pyx_string_tab[58]
-#define __pyx_n_u_reduce __pyx_string_tab[59]
-#define __pyx_n_u_reduce_cython __pyx_string_tab[60]
-#define __pyx_n_u_reduce_ex __pyx_string_tab[61]
-#define __pyx_n_u_self __pyx_string_tab[62]
-#define __pyx_n_u_set_name __pyx_string_tab[63]
-#define __pyx_n_u_setdefault __pyx_string_tab[64]
-#define __pyx_n_u_setstate __pyx_string_tab[65]
-#define __pyx_n_u_setstate_cython __pyx_string_tab[66]
-#define __pyx_n_u_struct __pyx_string_tab[67]
-#define __pyx_n_u_test __pyx_string_tab[68]
-#define __pyx_n_u_time __pyx_string_tab[69]
-#define __pyx_n_u_timestamp __pyx_string_tab[70]
-#define __pyx_n_u_values __pyx_string_tab[71]
-#define __pyx_kp_b_ __pyx_string_tab[72]
-#define __pyx_kp_b_0 __pyx_string_tab[73]
-#define __pyx_kp_b_Genesis_Block __pyx_string_tab[74]
-#define __pyx_kp_b_dummy_hash __pyx_string_tab[75]
-#define __pyx_kp_b_iso88591_A_4r_3d_D_AQ_D_AQ_iq_Q __pyx_string_tab[76]
-#define __pyx_kp_b_iso88591_A_4t1_aq_a_HBa_IQ_IQfD_4s_Ja_q_g __pyx_string_tab[77]
-#define __pyx_kp_b_iso88591_A_IQ_IQfD_4s_Ja_7_1_waq_gQa_XX_J __pyx_string_tab[78]
-#define __pyx_kp_b_iso88591_Q __pyx_string_tab[79]
+#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_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]
+#define __pyx_n_u_datetime __pyx_string_tab[33]
+#define __pyx_n_u_dopt_basics __pyx_string_tab[34]
+#define __pyx_n_u_dopt_basics_datetime __pyx_string_tab[35]
+#define __pyx_n_u_encode __pyx_string_tab[36]
+#define __pyx_n_u_from_ptr __pyx_string_tab[37]
+#define __pyx_n_u_fromtimestamp __pyx_string_tab[38]
+#define __pyx_n_u_func __pyx_string_tab[39]
+#define __pyx_n_u_get_block __pyx_string_tab[40]
+#define __pyx_n_u_getstate __pyx_string_tab[41]
+#define __pyx_n_u_hashlib __pyx_string_tab[42]
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+#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_py_block __pyx_string_tab[62]
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+#define __pyx_n_u_reduce_cython __pyx_string_tab[67]
+#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]
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+#define __pyx_n_u_struct __pyx_string_tab[75]
+#define __pyx_n_u_test __pyx_string_tab[76]
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+    /* "polluck_blockchain/placeholder_native.pyx":57
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@@ -3625,11 +3659,11 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock___cinit__
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+    /* "polluck_blockchain/placeholder_native.pyx":61
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 */
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 */
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 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) {
 
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@@ -3874,77 +3908,77 @@ static struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx
     }
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   __Pyx_GOTREF(__pyx_t_2);
 
-  /* "polluck_blockchain/placeholder_native.pyx":86
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 */
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-  /* "polluck_blockchain/placeholder_native.pyx":128
+  /* "polluck_blockchain/placeholder_native.pyx":135
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   return __pyx_r;
 }
 
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-  /* "polluck_blockchain/placeholder_native.pyx":138
+  /* "polluck_blockchain/placeholder_native.pyx":145
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  *         return self.BlockC.hash.decode("UTF-8")             # <<<<<<<<<<<<<<
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  *     # @hash.setter
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+  __pyx_t_1 = __Pyx_decode_cpp_string(__pyx_v_self->BlockC->hash, 0, PY_SSIZE_T_MAX, NULL, NULL, PyUnicode_DecodeUTF8); if (unlikely(!__pyx_t_1)) __PYX_ERR(0, 145, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":136
+  /* "polluck_blockchain/placeholder_native.pyx":143
  *     #     self._nonce = value
  * 
  *     @property             # <<<<<<<<<<<<<<
@@ -4395,15 +4609,15 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_4ha
 */
 
 /* Python wrapper */
-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_7__reduce_cython__(PyObject *__pyx_v_self, 
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_11__reduce_cython__(PyObject *__pyx_v_self, 
 #if CYTHON_METH_FASTCALL
 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
 #else
 PyObject *__pyx_args, PyObject *__pyx_kwds
 #endif
 ); /*proto*/
-static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_7PyBlock_7__reduce_cython__ = {"__reduce_cython__", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_7__reduce_cython__, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_7__reduce_cython__(PyObject *__pyx_v_self, 
+static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_7PyBlock_11__reduce_cython__ = {"__reduce_cython__", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_11__reduce_cython__, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_11__reduce_cython__(PyObject *__pyx_v_self, 
 #if CYTHON_METH_FASTCALL
 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
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+  __pyx_r = __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_10__reduce_cython__(((struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *)__pyx_v_self));
 
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+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) {
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 */
 
 /* Python wrapper */
-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_9__setstate_cython__(PyObject *__pyx_v_self, 
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_13__setstate_cython__(PyObject *__pyx_v_self, 
 #if CYTHON_METH_FASTCALL
 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
 #else
 PyObject *__pyx_args, PyObject *__pyx_kwds
 #endif
 ); /*proto*/
-static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_7PyBlock_9__setstate_cython__ = {"__setstate_cython__", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_9__setstate_cython__, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_9__setstate_cython__(PyObject *__pyx_v_self, 
+static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_7PyBlock_13__setstate_cython__ = {"__setstate_cython__", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_13__setstate_cython__, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_13__setstate_cython__(PyObject *__pyx_v_self, 
 #if CYTHON_METH_FASTCALL
 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
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-  __pyx_r = __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_8__setstate_cython__(((struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *)__pyx_v_self), __pyx_v___pyx_state);
+  __pyx_r = __pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_12__setstate_cython__(((struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *)__pyx_v_self), __pyx_v___pyx_state);
 
   /* function exit code */
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 }
 
-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_7PyBlock_8__setstate_cython__(CYTHON_UNUSED struct __pyx_obj_18polluck_blockchain_18placeholder_native_PyBlock *__pyx_v_self, CYTHON_UNUSED PyObject *__pyx_v___pyx_state) {
+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) {
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 }
 
-/* "polluck_blockchain/placeholder_native.pyx":156
+/* "polluck_blockchain/placeholder_native.pyx":163
  *     cdef bint _genesis_done
  * 
  *     def __cinit__(self):             # <<<<<<<<<<<<<<
@@ -4638,7 +4852,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
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-  /* "polluck_blockchain/placeholder_native.pyx":157
+  /* "polluck_blockchain/placeholder_native.pyx":164
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@@ -4647,7 +4861,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
 */
   __pyx_v_self->_difficulty = 1;
 
-  /* "polluck_blockchain/placeholder_native.pyx":158
+  /* "polluck_blockchain/placeholder_native.pyx":165
  *     def __cinit__(self):
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  *         self._index = <uint64_t>0             # <<<<<<<<<<<<<<
@@ -4656,7 +4870,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
 */
   __pyx_v_self->_index = ((uint64_t)0);
 
-  /* "polluck_blockchain/placeholder_native.pyx":159
+  /* "polluck_blockchain/placeholder_native.pyx":166
  *         self._difficulty = 1
  *         self._index = <uint64_t>0
  *         self._genesis_done = <bint>0             # <<<<<<<<<<<<<<
@@ -4665,7 +4879,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
 */
   __pyx_v_self->_genesis_done = 0;
 
-  /* "polluck_blockchain/placeholder_native.pyx":160
+  /* "polluck_blockchain/placeholder_native.pyx":167
  *         self._index = <uint64_t>0
  *         self._genesis_done = <bint>0
  *         self._chain = new unordered_map[uint64_t, Block*]()             # <<<<<<<<<<<<<<
@@ -4676,11 +4890,11 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
     __pyx_t_1 = new std::unordered_map<uint64_t,::Block *> ();
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     __Pyx_CppExn2PyErr();
-    __PYX_ERR(0, 160, __pyx_L1_error)
+    __PYX_ERR(0, 167, __pyx_L1_error)
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   __pyx_v_self->_chain = __pyx_t_1;
 
-  /* "polluck_blockchain/placeholder_native.pyx":161
+  /* "polluck_blockchain/placeholder_native.pyx":168
  *         self._genesis_done = <bint>0
  *         self._chain = new unordered_map[uint64_t, Block*]()
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@@ -4690,7 +4904,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
   __pyx_t_2 = (__pyx_v_self->_chain == NULL);
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-    /* "polluck_blockchain/placeholder_native.pyx":162
+    /* "polluck_blockchain/placeholder_native.pyx":169
  *         self._chain = new unordered_map[uint64_t, Block*]()
  *         if self._chain is NULL:
  *             raise MemoryError("Could not allocate hasmap")             # <<<<<<<<<<<<<<
@@ -4703,14 +4917,14 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
       PyObject *__pyx_callargs[2] = {__pyx_t_4, __pyx_mstate_global->__pyx_kp_u_Could_not_allocate_hasmap};
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-      if (unlikely(!__pyx_t_3)) __PYX_ERR(0, 162, __pyx_L1_error)
+      if (unlikely(!__pyx_t_3)) __PYX_ERR(0, 169, __pyx_L1_error)
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-    /* "polluck_blockchain/placeholder_native.pyx":161
+    /* "polluck_blockchain/placeholder_native.pyx":168
  *         self._genesis_done = <bint>0
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  *         if self._chain is NULL:             # <<<<<<<<<<<<<<
@@ -4719,7 +4933,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":156
+  /* "polluck_blockchain/placeholder_native.pyx":163
  *     cdef bint _genesis_done
  * 
  *     def __cinit__(self):             # <<<<<<<<<<<<<<
@@ -4740,7 +4954,7 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain___cin
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":164
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  * 
  *     def __init__(self, *args, **kwargs):             # <<<<<<<<<<<<<<
@@ -4788,12 +5002,12 @@ static int __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_2__in
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":167
- *         pass
- * 
+/* "polluck_blockchain/placeholder_native.pyx":176
+ *     # TODO add entries of map
+ *     # ownership is typically not transferred from the Blockchain extension class
  *     def __dealloc__(self):             # <<<<<<<<<<<<<<
+ *         cdef BcHashmap.iterator it = self._chain.begin()
  *         if self._chain is not NULL:
- *             del self._chain
 */
 
 /* Python wrapper */
@@ -4810,29 +5024,69 @@ static void __pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_5__d
 }
 
 static void __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_4__dealloc__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self) {
+  std::unordered_map<uint64_t,::Block *> ::iterator __pyx_v_it;
   int __pyx_t_1;
 
-  /* "polluck_blockchain/placeholder_native.pyx":168
- * 
+  /* "polluck_blockchain/placeholder_native.pyx":177
+ *     # ownership is typically not transferred from the Blockchain extension class
  *     def __dealloc__(self):
+ *         cdef BcHashmap.iterator it = self._chain.begin()             # <<<<<<<<<<<<<<
+ *         if self._chain is not NULL:
+ *             while it != self._chain.end():
+*/
+  __pyx_v_it = __pyx_v_self->_chain->begin();
+
+  /* "polluck_blockchain/placeholder_native.pyx":178
+ *     def __dealloc__(self):
+ *         cdef BcHashmap.iterator it = self._chain.begin()
  *         if self._chain is not NULL:             # <<<<<<<<<<<<<<
- *             del self._chain
- *             self._chain = NULL
+ *             while it != self._chain.end():
+ *                 del dereference(it).second
 */
   __pyx_t_1 = (__pyx_v_self->_chain != NULL);
   if (__pyx_t_1) {
 
-    /* "polluck_blockchain/placeholder_native.pyx":169
- *     def __dealloc__(self):
+    /* "polluck_blockchain/placeholder_native.pyx":179
+ *         cdef BcHashmap.iterator it = self._chain.begin()
  *         if self._chain is not NULL:
+ *             while it != self._chain.end():             # <<<<<<<<<<<<<<
+ *                 del dereference(it).second
+ *                 postincrement(it)
+*/
+    while (1) {
+      __pyx_t_1 = (__pyx_v_it != __pyx_v_self->_chain->end());
+      if (!__pyx_t_1) break;
+
+      /* "polluck_blockchain/placeholder_native.pyx":180
+ *         if self._chain is not NULL:
+ *             while it != self._chain.end():
+ *                 del dereference(it).second             # <<<<<<<<<<<<<<
+ *                 postincrement(it)
+ * 
+*/
+      delete (*__pyx_v_it).second;
+
+      /* "polluck_blockchain/placeholder_native.pyx":181
+ *             while it != self._chain.end():
+ *                 del dereference(it).second
+ *                 postincrement(it)             # <<<<<<<<<<<<<<
+ * 
+ *             del self._chain
+*/
+      (void)((__pyx_v_it++));
+    }
+
+    /* "polluck_blockchain/placeholder_native.pyx":183
+ *                 postincrement(it)
+ * 
  *             del self._chain             # <<<<<<<<<<<<<<
  *             self._chain = NULL
  * 
 */
     delete __pyx_v_self->_chain;
 
-    /* "polluck_blockchain/placeholder_native.pyx":170
- *         if self._chain is not NULL:
+    /* "polluck_blockchain/placeholder_native.pyx":184
+ * 
  *             del self._chain
  *             self._chain = NULL             # <<<<<<<<<<<<<<
  * 
@@ -4840,27 +5094,27 @@ static void __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_4__d
 */
     __pyx_v_self->_chain = NULL;
 
-    /* "polluck_blockchain/placeholder_native.pyx":168
- * 
+    /* "polluck_blockchain/placeholder_native.pyx":178
  *     def __dealloc__(self):
+ *         cdef BcHashmap.iterator it = self._chain.begin()
  *         if self._chain is not NULL:             # <<<<<<<<<<<<<<
- *             del self._chain
- *             self._chain = NULL
+ *             while it != self._chain.end():
+ *                 del dereference(it).second
 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":167
- *         pass
- * 
+  /* "polluck_blockchain/placeholder_native.pyx":176
+ *     # TODO add entries of map
+ *     # ownership is typically not transferred from the Blockchain extension class
  *     def __dealloc__(self):             # <<<<<<<<<<<<<<
+ *         cdef BcHashmap.iterator it = self._chain.begin()
  *         if self._chain is not NULL:
- *             del self._chain
 */
 
   /* function exit code */
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":172
+/* "polluck_blockchain/placeholder_native.pyx":186
  *             self._chain = NULL
  * 
  *     def __len__(self):             # <<<<<<<<<<<<<<
@@ -4886,17 +5140,17 @@ static Py_ssize_t __pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchai
 static Py_ssize_t __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_6__len__(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self) {
   Py_ssize_t __pyx_r;
 
-  /* "polluck_blockchain/placeholder_native.pyx":173
+  /* "polluck_blockchain/placeholder_native.pyx":187
  * 
  *     def __len__(self):
  *         return self._index + 1             # <<<<<<<<<<<<<<
  * 
- *     @property
+ *     def print_key_value_pair(self):
 */
   __pyx_r = (__pyx_v_self->_index + 1);
   goto __pyx_L0;
 
-  /* "polluck_blockchain/placeholder_native.pyx":172
+  /* "polluck_blockchain/placeholder_native.pyx":186
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  * 
  *     def __len__(self):             # <<<<<<<<<<<<<<
@@ -4909,9 +5163,191 @@ static Py_ssize_t __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchai
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":175
+/* "polluck_blockchain/placeholder_native.pyx":189
  *         return self._index + 1
  * 
+ *     def print_key_value_pair(self):             # <<<<<<<<<<<<<<
+ *         cdef BcHashmap.iterator it = self._chain.begin()
+ *         cdef Block *block
+*/
+
+/* Python wrapper */
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_9print_key_value_pair(PyObject *__pyx_v_self, 
+#if CYTHON_METH_FASTCALL
+PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
+#else
+PyObject *__pyx_args, PyObject *__pyx_kwds
+#endif
+); /*proto*/
+static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_10Blockchain_9print_key_value_pair = {"print_key_value_pair", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_9print_key_value_pair, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_9print_key_value_pair(PyObject *__pyx_v_self, 
+#if CYTHON_METH_FASTCALL
+PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
+#else
+PyObject *__pyx_args, PyObject *__pyx_kwds
+#endif
+) {
+  #if !CYTHON_METH_FASTCALL
+  CYTHON_UNUSED Py_ssize_t __pyx_nargs;
+  #endif
+  CYTHON_UNUSED PyObject *const *__pyx_kwvalues;
+  PyObject *__pyx_r = 0;
+  __Pyx_RefNannyDeclarations
+  __Pyx_RefNannySetupContext("print_key_value_pair (wrapper)", 0);
+  #if !CYTHON_METH_FASTCALL
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@@ -5237,18 +5673,18 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
 */
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+  /* "polluck_blockchain/placeholder_native.pyx":215
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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, 215, __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, 215, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":192
+  /* "polluck_blockchain/placeholder_native.pyx":216
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   __Pyx_XDECREF(__pyx_r);
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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, 192, __pyx_L1_error)
+  __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, 216, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":187
+  /* "polluck_blockchain/placeholder_native.pyx":211
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   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":194
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  *     cdef void add_block(self, Block *block):             # <<<<<<<<<<<<<<
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 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":195
+  /* "polluck_blockchain/placeholder_native.pyx":219
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@@ -5303,7 +5739,7 @@ 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":196
+  /* "polluck_blockchain/placeholder_native.pyx":220
  *     cdef void add_block(self, Block *block):
  *         self._chain[0][block.index] = block
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@@ -5312,7 +5748,7 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
 */
   if (__pyx_v_self->_genesis_done) {
 
-    /* "polluck_blockchain/placeholder_native.pyx":197
+    /* "polluck_blockchain/placeholder_native.pyx":221
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 */
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-    /* "polluck_blockchain/placeholder_native.pyx":196
+    /* "polluck_blockchain/placeholder_native.pyx":220
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@@ -5330,7 +5766,7 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
 */
   }
 
-  /* "polluck_blockchain/placeholder_native.pyx":194
+  /* "polluck_blockchain/placeholder_native.pyx":218
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  * 
  *     cdef void add_block(self, Block *block):             # <<<<<<<<<<<<<<
@@ -5341,7 +5777,7 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
   /* function exit code */
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":199
+/* "polluck_blockchain/placeholder_native.pyx":223
  *             self._index += 1
  * 
  *     def create_genesis_block(self):             # <<<<<<<<<<<<<<
@@ -5350,15 +5786,15 @@ static void __pyx_f_18polluck_blockchain_18placeholder_native_10Blockchain_add_b
 */
 
 /* Python wrapper */
-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_11create_genesis_block(PyObject *__pyx_v_self, 
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 #if CYTHON_METH_FASTCALL
 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
 #else
 PyObject *__pyx_args, PyObject *__pyx_kwds
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 ); /*proto*/
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-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_11create_genesis_block(PyObject *__pyx_v_self, 
+static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_10Blockchain_13create_genesis_block = {"create_genesis_block", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_13create_genesis_block, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_13create_genesis_block(PyObject *__pyx_v_self, 
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 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
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+  __pyx_r = __pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_12create_genesis_block(((struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *)__pyx_v_self));
 
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-static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_10create_genesis_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self) {
+static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain_12create_genesis_block(struct __pyx_obj_18polluck_blockchain_18placeholder_native_Blockchain *__pyx_v_self) {
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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, 226, __pyx_L1_error)
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   __Pyx_DECREF(__pyx_t_3); __pyx_t_3 = 0;
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+  __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)
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-  __pyx_t_6 = __Pyx_PyFloat_AsDouble(__pyx_t_1); if (unlikely((__pyx_t_6 == (double)-1) && PyErr_Occurred())) __PYX_ERR(0, 202, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":204
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  *             datetime.datetime(2025, 12, 1, 12, 0, 0).timestamp(),
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  *             "0".encode("UTF-8"),
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 */
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+  __pyx_t_7 = __pyx_convert_string_from_py_6libcpp_6string_std__in_string(__pyx_mstate_global->__pyx_kp_b_Genesis_Block); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 228, __pyx_L1_error)
 
-  /* "polluck_blockchain/placeholder_native.pyx":205
+  /* "polluck_blockchain/placeholder_native.pyx":229
  *             0,
  *             "Genesis Block".encode("UTF-8"),
  *             "0".encode("UTF-8"),             # <<<<<<<<<<<<<<
  *             "".encode("UTF-8"),
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 */
-  __pyx_t_8 = __pyx_convert_string_from_py_6libcpp_6string_std__in_string(__pyx_mstate_global->__pyx_kp_b_0); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 205, __pyx_L1_error)
+  __pyx_t_8 = __pyx_convert_string_from_py_6libcpp_6string_std__in_string(__pyx_mstate_global->__pyx_kp_b_0); if (unlikely(PyErr_Occurred())) __PYX_ERR(0, 229, __pyx_L1_error)
 
-  /* "polluck_blockchain/placeholder_native.pyx":206
+  /* "polluck_blockchain/placeholder_native.pyx":230
  *             "Genesis Block".encode("UTF-8"),
  *             "0".encode("UTF-8"),
  *             "".encode("UTF-8"),             # <<<<<<<<<<<<<<
  *         )
- *         block.hash = <string>"dummy hash".encode("UTF-8")
+ *         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, 206, __pyx_L1_error)
+  __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)
 
-  /* "polluck_blockchain/placeholder_native.pyx":200
+  /* "polluck_blockchain/placeholder_native.pyx":224
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  *     def create_genesis_block(self):
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@@ -5477,39 +5913,39 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
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-    __PYX_ERR(0, 200, __pyx_L1_error)
+    __PYX_ERR(0, 224, __pyx_L1_error)
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-  /* "polluck_blockchain/placeholder_native.pyx":208
+  /* "polluck_blockchain/placeholder_native.pyx":232
  *             "".encode("UTF-8"),
  *         )
- *         block.hash = <string>"dummy hash".encode("UTF-8")             # <<<<<<<<<<<<<<
+ *         block.hash = "dummy hash".encode("UTF-8")             # <<<<<<<<<<<<<<
  *         self.add_block(block)
- *         self._genesis_done = <bint>1
+ *         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, 208, __pyx_L1_error)
-  __pyx_v_block->hash = ((std::string)__pyx_t_9);
+  __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_v_block->hash = __PYX_STD_MOVE_IF_SUPPORTED(__pyx_t_9);
 
-  /* "polluck_blockchain/placeholder_native.pyx":209
+  /* "polluck_blockchain/placeholder_native.pyx":233
  *         )
- *         block.hash = <string>"dummy hash".encode("UTF-8")
+ *         block.hash = "dummy hash".encode("UTF-8")
  *         self.add_block(block)             # <<<<<<<<<<<<<<
- *         self._genesis_done = <bint>1
+ *         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, 209, __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, 233, __pyx_L1_error)
 
-  /* "polluck_blockchain/placeholder_native.pyx":210
- *         block.hash = <string>"dummy hash".encode("UTF-8")
+  /* "polluck_blockchain/placeholder_native.pyx":234
+ *         block.hash = "dummy hash".encode("UTF-8")
  *         self.add_block(block)
- *         self._genesis_done = <bint>1             # <<<<<<<<<<<<<<
+ *         self._genesis_done = True             # <<<<<<<<<<<<<<
  * 
  *     def new_block(self, data):
 */
   __pyx_v_self->_genesis_done = 1;
 
-  /* "polluck_blockchain/placeholder_native.pyx":199
+  /* "polluck_blockchain/placeholder_native.pyx":223
  *             self._index += 1
  * 
  *     def create_genesis_block(self):             # <<<<<<<<<<<<<<
@@ -5533,8 +5969,8 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
   return __pyx_r;
 }
 
-/* "polluck_blockchain/placeholder_native.pyx":212
- *         self._genesis_done = <bint>1
+/* "polluck_blockchain/placeholder_native.pyx":236
+ *         self._genesis_done = True
  * 
  *     def new_block(self, data):             # <<<<<<<<<<<<<<
  *         if not self._genesis_done:
@@ -5542,15 +5978,15 @@ static PyObject *__pyx_pf_18polluck_blockchain_18placeholder_native_10Blockchain
 */
 
 /* Python wrapper */
-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_13new_block(PyObject *__pyx_v_self, 
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_15new_block(PyObject *__pyx_v_self, 
 #if CYTHON_METH_FASTCALL
 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
 #else
 PyObject *__pyx_args, PyObject *__pyx_kwds
 #endif
 ); /*proto*/
-static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_10Blockchain_13new_block = {"new_block", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_13new_block, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
-static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_13new_block(PyObject *__pyx_v_self, 
+static PyMethodDef __pyx_mdef_18polluck_blockchain_18placeholder_native_10Blockchain_15new_block = {"new_block", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_15new_block, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0};
+static PyObject *__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_15new_block(PyObject *__pyx_v_self, 
 #if CYTHON_METH_FASTCALL
 PyObject *const *__pyx_args, Py_ssize_t __pyx_nargs, PyObject *__pyx_kwds
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+  {"__setstate_cython__", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_13__setstate_cython__, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0},
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+  {Py_tp_str, (void *)__pyx_pw_18polluck_blockchain_18placeholder_native_7PyBlock_9__str__},
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   0, /*tp_getattr*/
   0, /*tp_setattr*/
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-  0, /*tp_repr*/
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   0, /*tp_as_sequence*/
   0, /*tp_as_mapping*/
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 static PyMethodDef __pyx_methods_18polluck_blockchain_18placeholder_native_Blockchain[] = {
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-  {"new_block", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_13new_block, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0},
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+  {"print_key_value_pair", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_9print_key_value_pair, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0},
+  {"get_block", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_11get_block, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0},
+  {"create_genesis_block", (PyCFunction)(void(*)(void))(__Pyx_PyCFunction_FastCallWithKeywords)__pyx_pw_18polluck_blockchain_18placeholder_native_10Blockchain_13create_genesis_block, __Pyx_METH_FASTCALL|METH_KEYWORDS, 0},
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-  /* "polluck_blockchain/placeholder_native.pyx":187
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+const char* const cstring = "x\332}SKo\0231\020VT\004\021\244@\240\242B<\264\251@\342\325\024D%8 P\037<\212x\005\265\022B\225,\307v\022S\257\275Y{Cr\343\230\243\217>\356q\2179\36238\356\261?\205\361f\233\026\245\342\260\353\3173\343\36173\2377\204P\004\033\256d\240:A\0336\007\201j\377`\304\004\035\314\005\243[*\0214\220\312\004x\032\312\202\036\326!\216\266b\34678\3502\3114\327\345\341\016\217\265i\356H\312\206\301\000\213\204\005\340R\211)\322\253DR\375e\264\351#\357\355\355\276Y}~\377\325KJ\271\306m\301\230\364\377.\341z\212\250T\001e\035\234\010\023 \0243\232\020\206P@!\245Q\300H\256\232\230\0178\026\340%\\r\203\220\216\311Z\244\204H\310\001*\350\220\036\346r-\022\230\260\236\022\224\305HB\261\003\326\214F\303\027\032\316\313\256VIL\330\313\315Y\3701j\316\256%#\323S\022\241\177|\232\031m\240\007\247yI\321\035T\366fJ\346\204\273\313\314\234M\262\237s\266\010\030\032t\300F\250\350%\2120\217\313\376\225\313<\307c\307\034A\357\034\302\267\315\211A\237\330\320|e\235\335\235\217\257\277\177\376\364\032\355\355na=\222\204\253&Q1\214\214\003\367i\027\005@\304%214\262\215\301rJy\024\033\014\0373<dTEP \326\234\350\023\260y\344f\222(\030m\254B\024\231\330\257\336\n\\\303\010\241N\"\tB\263\016\025pZ\006\002\345\365\004os:\344^`\010\256\236Q\345\206\033\026j\204Bh\234/5T4\021\314#\211CXg\375\365\000R\200\202\010\213\240\230y\3054\347\025\023\251(\212\331`\032T O\306\003\256\022]n`X\247M,\032\035\225\002\262Ce-\036\016\214\027\272\247\330O\260\230\322<\226\372\334dg\006(\275\330D\261\037\262\350\024\243.\313\004T\276\232\023\002@\247\210\001\344\237\200\014\220\201\306\303\037\0060\033BA]?~[\276\354BO4\t\303\221\177\373\275_\033y\365\302x}\034\333+\366\251\245n\305m\247\225\274v\305>p\033\256uX\275\t\373Z\266\221\265\362\3525\313]?]\314ZGg\214}\342#\0379\354\372\207\325F\272\224\356O\352\223;\023\234W\203\364|\326\360\313\231\364]\266\231a\237h'm\345\265\305\274\266dw\\\313u\322\355l![\317\364de\362\3767.<\227\3559\333w\225\002_\034wm\313\302\301\332\370\275\305\266\357/-s\\\266\225\377e\271\341\236\245""\215\024\250]\032\377\364'O\344Z\034\177\263\373\351rV\311\352\371Qb\000\177j\267\\Q\325\335t7[\236\234\235@\350\3051\261W\355\266;\347\214\317U\267u(\224\244u\177\363\207t\301\333n;\236\366\263\312\324\331\310k\327]\3355~U\3623\347\307\017m\353/t\0371\325";
+    PyObject *data = __Pyx_DecompressString(cstring, 786, 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 (1272 bytes) */
-const char* const bytes = "Allocation of block object failedCould not allocate hasmapCreate a genesis block first.Index value is out of boundsUTF-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_blockPyBlockPyBlock.__reduce_cython__PyBlock.__setstate_cython____Pyx_PyDict_NextRefTIMEZONE_UTCasyncio.coroutinesblockcline_in_tracebackcreate_genesis_blockdatadatetimedopt_basicsdopt_basics.datetimeencodefrom_ptrfromtimestamp__func__get_block__getstate__hashlibidxindex_is_coroutineitems__main____module____name__new_blocknew_idxnoncepackpolluck_blockchain.placeholder_nativepopprev_blockprev_hashprevious_hash__pyx_state__pyx_vtable____qualname____reduce____reduce_cython____reduce_ex__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\220X\230\\\250\027\260\001\260\021\330\010\014\210J\220a\220q\330\010\014\320\014\035\230V\2401\200\001\330\004\n\210+\220Q";
+    #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";
     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 < 72; i++) {
+    for (int i = 0; i < 80; i++) {
       Py_ssize_t bytes_length = index[i].length;
       PyObject *string = PyUnicode_DecodeUTF8(bytes + pos, bytes_length, NULL);
-      if (likely(string) && i >= 14) PyUnicode_InternInPlace(&string);
+      if (likely(string) && i >= 16) PyUnicode_InternInPlace(&string);
       if (unlikely(!string)) {
         Py_XDECREF(data);
         __PYX_ERR(0, 1, __pyx_L1_error)
@@ -7080,7 +7537,7 @@ const char* const bytes = "Allocation of block object failedCould not allocate h
       stringtab[i] = string;
       pos += bytes_length;
     }
-    for (int i = 72; i < 80; i++) {
+    for (int i = 80; i < 89; i++) {
       Py_ssize_t bytes_length = index[i].length;
       PyObject *string = PyBytes_FromStringAndSize(bytes + pos, bytes_length);
       stringtab[i] = string;
@@ -7091,15 +7548,15 @@ const char* const bytes = "Allocation of block object failedCould not allocate h
       }
     }
     Py_XDECREF(data);
-    for (Py_ssize_t i = 0; i < 80; i++) {
+    for (Py_ssize_t i = 0; i < 89; i++) {
       if (unlikely(PyObject_Hash(stringtab[i]) == -1)) {
         __PYX_ERR(0, 1, __pyx_L1_error)
       }
     }
     #if CYTHON_IMMORTAL_CONSTANTS
     {
-      PyObject **table = stringtab + 72;
-      for (Py_ssize_t i=0; i<8; ++i) {
+      PyObject **table = stringtab + 80;
+      for (Py_ssize_t i=0; i<9; ++i) {
         #if CYTHON_COMPILING_IN_CPYTHON_FREETHREADING
         Py_SET_REFCNT(table[i], _Py_IMMORTAL_REFCNT_LOCAL);
         #else
@@ -7168,29 +7625,34 @@ static int __Pyx_CreateCodeObjects(__pyx_mstatetype *__pyx_mstate) {
     __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;
   }
   {
-    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 3, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 187};
+    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 4, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 189};
+    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;
+  }
+  {
+    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 3, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 211};
     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[2] = __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[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_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;
   }
   {
-    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 2, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 199};
+    const __Pyx_PyCode_New_function_description descr = {1, 0, 0, 2, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 223};
     PyObject* const varnames[] = {__pyx_mstate->__pyx_n_u_self, __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_create_genesis_block, __pyx_mstate->__pyx_kp_b_iso88591_A_IQ_IQfD_4s_Ja_7_1_waq_gQa_XX_J, 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_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;
   }
   {
-    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 6, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 212};
+    const __Pyx_PyCode_New_function_description descr = {2, 0, 0, 6, (unsigned int)(CO_OPTIMIZED|CO_NEWLOCALS), 236};
     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[4] = __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[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_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;
   }
   {
     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[5] = __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[5])) goto bad;
+    __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;
   }
   {
     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[6] = __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[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_setstate_cython, __pyx_mstate->__pyx_kp_b_iso88591_Q, tuple_dedup_map); if (unlikely(!__pyx_mstate_global->__pyx_codeobj_tab[7])) goto bad;
   }
   Py_DECREF(tuple_dedup_map);
   return 0;
@@ -7408,7 +7870,7 @@ static CYTHON_INLINE PyObject* __Pyx_PyObject_GetAttrStrNoError(PyObject* obj, P
 #endif
 }
 
-/* GetBuiltinName (used by GetModuleGlobalName) */
+/* GetBuiltinName */
 static PyObject *__Pyx_GetBuiltinName(PyObject *name) {
     PyObject* result = __Pyx_PyObject_GetAttrStrNoError(__pyx_mstate_global->__pyx_b, name);
     if (unlikely(!result) && !PyErr_Occurred()) {
@@ -8673,6 +9135,84 @@ static int __Pyx_CheckKeywordStrings(
 #endif
 }
 
+/* JoinPyUnicode */
+static PyObject* __Pyx_PyUnicode_Join(PyObject** values, Py_ssize_t value_count, Py_ssize_t result_ulength,
+                                      Py_UCS4 max_char) {
+#if CYTHON_USE_UNICODE_INTERNALS && CYTHON_ASSUME_SAFE_MACROS && !CYTHON_AVOID_BORROWED_REFS
+    PyObject *result_uval;
+    int result_ukind, kind_shift;
+    Py_ssize_t i, char_pos;
+    void *result_udata;
+    if (max_char > 1114111) max_char = 1114111;
+    result_uval = PyUnicode_New(result_ulength, max_char);
+    if (unlikely(!result_uval)) return NULL;
+    result_ukind = (max_char <= 255) ? PyUnicode_1BYTE_KIND : (max_char <= 65535) ? PyUnicode_2BYTE_KIND : PyUnicode_4BYTE_KIND;
+    kind_shift = (result_ukind == PyUnicode_4BYTE_KIND) ? 2 : result_ukind - 1;
+    result_udata = PyUnicode_DATA(result_uval);
+    assert(kind_shift == 2 || kind_shift == 1 || kind_shift == 0);
+    if (unlikely((PY_SSIZE_T_MAX >> kind_shift) - result_ulength < 0))
+        goto overflow;
+    char_pos = 0;
+    for (i=0; i < value_count; i++) {
+        int ukind;
+        Py_ssize_t ulength;
+        void *udata;
+        PyObject *uval = values[i];
+        #if !CYTHON_COMPILING_IN_LIMITED_API
+        if (__Pyx_PyUnicode_READY(uval) == (-1))
+            goto bad;
+        #endif
+        ulength = __Pyx_PyUnicode_GET_LENGTH(uval);
+        #if !CYTHON_ASSUME_SAFE_SIZE
+        if (unlikely(ulength < 0)) goto bad;
+        #endif
+        if (unlikely(!ulength))
+            continue;
+        if (unlikely((PY_SSIZE_T_MAX >> kind_shift) - ulength < char_pos))
+            goto overflow;
+        ukind = __Pyx_PyUnicode_KIND(uval);
+        udata = __Pyx_PyUnicode_DATA(uval);
+        if (ukind == result_ukind) {
+            memcpy((char *)result_udata + (char_pos << kind_shift), udata, (size_t) (ulength << kind_shift));
+        } else {
+            #if PY_VERSION_HEX >= 0x030d0000
+            if (unlikely(PyUnicode_CopyCharacters(result_uval, char_pos, uval, 0, ulength) < 0)) goto bad;
+            #elif CYTHON_COMPILING_IN_CPYTHON || defined(_PyUnicode_FastCopyCharacters)
+            _PyUnicode_FastCopyCharacters(result_uval, char_pos, uval, 0, ulength);
+            #else
+            Py_ssize_t j;
+            for (j=0; j < ulength; j++) {
+                Py_UCS4 uchar = __Pyx_PyUnicode_READ(ukind, udata, j);
+                __Pyx_PyUnicode_WRITE(result_ukind, result_udata, char_pos+j, uchar);
+            }
+            #endif
+        }
+        char_pos += ulength;
+    }
+    return result_uval;
+overflow:
+    PyErr_SetString(PyExc_OverflowError, "join() result is too long for a Python string");
+bad:
+    Py_DECREF(result_uval);
+    return NULL;
+#else
+    Py_ssize_t i;
+    PyObject *result = NULL;
+    PyObject *value_tuple = PyTuple_New(value_count);
+    if (unlikely(!value_tuple)) return NULL;
+    CYTHON_UNUSED_VAR(max_char);
+    CYTHON_UNUSED_VAR(result_ulength);
+    for (i=0; i<value_count; i++) {
+        if (__Pyx_PyTuple_SET_ITEM(value_tuple, i, values[i]) != (0)) goto bad;
+        Py_INCREF(values[i]);
+    }
+    result = PyUnicode_Join(__pyx_mstate_global->__pyx_empty_unicode, value_tuple);
+bad:
+    Py_DECREF(value_tuple);
+    return result;
+#endif
+}
+
 /* decode_c_bytes (used by decode_cpp_string) */
 static CYTHON_INLINE PyObject* __Pyx_decode_c_bytes(
          const char* cstring, Py_ssize_t length, Py_ssize_t start, Py_ssize_t stop,
@@ -11673,7 +12213,7 @@ __Pyx_PyType_GetFullyQualifiedName(PyTypeObject* tp)
         result = name;
         name = NULL;
     } else {
-        result = __Pyx_NewRef(__pyx_mstate_global->__pyx_kp_u__2);
+        result = __Pyx_NewRef(__pyx_mstate_global->__pyx_kp_u__3);
     }
     goto done;
 }
diff --git a/src/polluck_blockchain/placeholder_native.pyx b/src/polluck_blockchain/placeholder_native.pyx
index 0f12a00..f6ec72a 100644
--- a/src/polluck_blockchain/placeholder_native.pyx
+++ b/src/polluck_blockchain/placeholder_native.pyx
@@ -17,6 +17,7 @@ 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 cython.operator import postincrement, dereference
 
 ctypedef unsigned long ULong
 ctypedef unordered_map[uint64_t, Block*] BcHashmap
@@ -92,6 +93,12 @@ cdef class PyBlock:
 
         return py_block
 
+    def __repr__(self):
+        return f"PyBlock({self.index, self.timestamp, self.nonce, self.data})"
+    
+    def __str__(self):
+        return self.__repr__()
+
     # cpdef _perform_hash(self):
     #     parts = bytearray()
     #     parts.extend(self._index.to_bytes(8, "big"))
@@ -164,15 +171,29 @@ cdef class Blockchain:
     def __init__(self, *args, **kwargs):
         pass
     
-    # TODO add entries of map
-    # ownership is typically not transferred from the Blockchain extension class
     def __dealloc__(self):
+        # ownership is typically not transferred from the Blockchain extension class
+        cdef BcHashmap.iterator it = self._chain.begin()
         if self._chain is not NULL:
+            while it != self._chain.end():
+                del dereference(it).second
+                postincrement(it)
+
             del self._chain
             self._chain = NULL
 
     def __len__(self):
         return self._index + 1
+    
+    def print_key_value_pair(self):
+        cdef BcHashmap.iterator it = self._chain.begin()
+        cdef Block *block
+        while it != self._chain.end():
+            print(dereference(it).first)
+            block = dereference(it).second
+            py_block = PyBlock.from_ptr(block)
+            print(py_block)
+            postincrement(it)
 
     @property
     def genesis_done(self):
@@ -207,9 +228,9 @@ cdef class Blockchain:
             "0".encode("UTF-8"),
             "".encode("UTF-8"),
         )
-        block.hash = <string>"dummy hash".encode("UTF-8")
+        block.hash = "dummy hash".encode("UTF-8")
         self.add_block(block)
-        self._genesis_done = <bint>1
+        self._genesis_done = True
 
     def new_block(self, data):
         if not self._genesis_done: