code: def add_user_to_group(self, user_name, group_name):
          
  
          res = self._make_ocs_request(
              'POST',
              self.OCS_SERVICE_CLOUD,
              'users/' + user_name + '/groups',
              data={'groupid': group_name}
          )
  
          if res.status_code == 200:
              tree = ET.fromstring(res.content)
              self._check_ocs_status(tree, [100])
              return True
  
          raise HTTPResponseError(res)
docs: Adds a user to a group.
  
          :param user_name:  name of user to be added
          :param group_name:  name of group user is to be added to
          :returns: True if user added
          :raises: HTTPResponseError in case an HTTP error status was returned