code: def start_worker(self):
          
          if not self.include_rq:
              return None
  
          worker = Worker(queues=self.queues,
                          connection=self.connection)
          worker_pid_path = current_app.config.get(
              "{}_WORKER_PID".format(self.config_prefix), 'rl_worker.pid'
          )
  
          try:
              worker_pid_file = open(worker_pid_path, 'r')
              worker_pid = int(worker_pid_file.read())
              print("Worker already started with PID=%d" % worker_pid)
              worker_pid_file.close()
  
              return worker_pid
  
          except (IOError, TypeError):
              self.worker_process = Process(target=worker_wrapper, kwargs={
                  'worker_instance': worker,
                  'pid_path': worker_pid_path
              })
              self.worker_process.start()
              worker_pid_file = open(worker_pid_path, 'w')
              worker_pid_file.write("%d" % self.worker_process.pid)
              worker_pid_file.close()
  
              print("Start a worker process with PID=%d" %
                    self.worker_process.pid)
  
              return self.worker_process.pid
docs: Trigger new process as a RQ worker.