code: def _unpack_bytes(bytes):
      
      if bytes == b'':
          return 0
      int_length = 4
      len_diff = int_length - len(bytes)
      bytes = bytes + len_diff * b'\x00'
      return struct.unpack("<L", bytes)[0]
docs: Unpack a set of bytes into an integer. First pads to 4 bytes.
      Little endian.