code: public function addGroupsToTask($process_id, $task_id, $task_add_groups_item)
      {
          list($response) = $this->addGroupsToTaskWithHttpInfo($process_id, $task_id, $task_add_groups_item);
          return $response;
      }
docs: Operation addGroupsToTask
  
  
  
  @param string $process_id Process ID (required)
  @param string $task_id ID of the task to be modified (required)
  @param \ProcessMaker\PMIO\Model\TaskAddGroupsItem $task_add_groups_item JSON API with Group IDs to add (required)
  @return \ProcessMaker\PMIO\Model\ResultSuccess
  @throws \ProcessMaker\PMIO\ApiException on non-2xx response