public function modify($resourceName, Google_Service_PeopleService_ModifyContactGroupMembersRequest $postBody, $optParams = array())
  {
    $params = array('resourceName' => $resourceName, 'postBody' => $postBody);
    $params = array_merge($params, $optParams);
    return $this->call('modify', array($params), "Google_Service_PeopleService_ModifyContactGroupMembersResponse");
  }