Update a specific comment. This can be used to edit the content of an
        existing comment.

def update_comment(self, comment_id, body):
        """
        Update a specific comment. This can be used to edit the content of an
        existing comment.
        """
        path = '/msg/update_comment'
        req = ET.Element('request')
        ET.SubElement(req, 'comment_id').text = str(int(comment_id))
        comment = ET.SubElement(req, 'comment')
        ET.SubElement(comment, 'body').text = str(body)
        return self._request(path, req)