Update a canned comment

        :type id_number: int
        :param id_number: canned comment ID number

        :type new_value: str
        :param new_value: New canned comment value

        :type metadata: str
        :param metadata: Optional metadata

        :rtype: dict
        :return: an empty dictionary

def update_comment(self, id_number, new_value, metadata=None):
        """
        Update a canned comment

        :type id_number: int
        :param id_number: canned comment ID number

        :type new_value: str
        :param new_value: New canned comment value

        :type metadata: str
        :param metadata: Optional metadata

        :rtype: dict
        :return: an empty dictionary
        """
        data = {
            'id': id_number,
            'new_comment': new_value
        }

        if metadata is not None:
            data['metadata'] = metadata

        return self.post('updateComment', data)