code: def _ParseOrMerge(self, lines, message):
      
      tokenizer = _Tokenizer(lines)
      while not tokenizer.AtEnd():
        self._MergeField(tokenizer, message)
docs: Converts an text representation of a protocol message into a message.
  
      Args:
        lines: Lines of a message's text representation.
        message: A protocol buffer message to merge into.
  
      Raises:
        ParseError: On text parsing problems.