code: def create_comment(self, post_id, body):
          
          path = '/msg/create_comment'
          req = ET.Element('request')
          comment = ET.SubElement(req, 'comment')
          ET.SubElement(comment, 'post-id').text = str(int(post_id))
          ET.SubElement(comment, 'body').text = str(body)
          return self._request(path, req)
docs: Create a new comment, associating it with a specific message.