code: def needs_fixed_byte(self, byte, value):
          
          assert isinstance(byte, int)
          assert isinstance(value, int)
          assert byte >= 0 and value >= 0
          assert byte <= 0xff and value <= 0xff
          if byte != value:
              self.parser_error("expects " + chr(value) + " in byte " + chr(byte))
docs: :return: None