Set the message format
        :param message_format: The format to set
        :type  message_format: str

def format(self, message_format):
        """
        Set the message format
        :param message_format: The format to set
        :type  message_format: str
        """
        if message_format not in self.formats:
            self._log.error('Invalid Message format specified: {format}'.format(format=message_format))
            return

        self._log.debug('Setting message format to {format}'.format(format=message_format))
        self._format = message_format