test: refactor: remove binascii from test_framework

test/functional/test_framework/blocktools.py

@@ -4,7 +4,6 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Utilities for manipulating blocks and transactions."""
 
-from binascii import a2b_hex
 import struct
 import time
 import unittest
@@ -73,7 +72,7 @@ def create_block(hashprev=None, coinbase=None, ntime=None, *, version=None, tmpl
     block.nTime = ntime or tmpl.get('curtime') or int(time.time() + 600)
     block.hashPrevBlock = hashprev or int(tmpl['previousblockhash'], 0x10)
     if tmpl and not tmpl.get('bits') is None:
-        block.nBits = struct.unpack('>I', a2b_hex(tmpl['bits']))[0]
+        block.nBits = struct.unpack('>I', bytes.fromhex(tmpl['bits']))[0]
     else:
         block.nBits = 0x207fffff  # difficulty retargeting is disabled in REGTEST chainparams
     if coinbase is None: