code: public function addGateway($process_id, $gateway_create_item)
      {
          list($response) = $this->addGatewayWithHttpInfo($process_id, $gateway_create_item);
          return $response;
      }
docs: Operation addGateway
  
  
  
  @param string $process_id ID of the process related to the gateway (required)
  @param \ProcessMaker\PMIO\Model\GatewayCreateItem $gateway_create_item JSON API response with the gateway object to add (required)
  @return \ProcessMaker\PMIO\Model\GatewayItem
  @throws \ProcessMaker\PMIO\ApiException on non-2xx response