code: def run_experiment(self):
          
          try:
              self.sign_up()
              self.participate()
              if self.sign_off():
                  self.complete_experiment("worker_complete")
              else:
                  self.complete_experiment("worker_failed")
          finally:
              self.driver.quit()
docs: Sign up, run the ``participate`` method, then sign off and close
          the driver.