code: public function addFlow($process_id, $flow_create_item)
      {
          list($response) = $this->addFlowWithHttpInfo($process_id, $flow_create_item);
          return $response;
      }
docs: Operation addFlow
  
  
  
  @param string $process_id ID of the process related to the flow (required)
  @param \ProcessMaker\PMIO\Model\FlowCreateItem $flow_create_item JSON API response with the Flow object to add (required)
  @return \ProcessMaker\PMIO\Model\FlowItem
  @throws \ProcessMaker\PMIO\ApiException on non-2xx response