code: def add_trial(self, trial):
          
          trial.set_verbose(self._verbose)
          self._trials.append(trial)
          with warn_if_slow("scheduler.on_trial_add"):
              self._scheduler_alg.on_trial_add(self, trial)
          self.trial_executor.try_checkpoint_metadata(trial)
docs: Adds a new trial to this TrialRunner.
  
          Trials may be added at any time.
  
          Args:
              trial (Trial): Trial to queue.