def append(self, message_level, message_text):
        """ Adds a message level/text pair to this MessagesHeader """
        if not message_level in MessagesHeader._message_levels:
            raise ValueError(message_level % 'message_level="%s"')
        self._messages.append((message_level, message_text))
dataset/ETHPy150Open hvandenb/splunk-elasticsearch/search-elasticsearch/bin/splunklib/searchcommands/search_command_internals.py/MessagesHeader.append/swapped operands of `%`