code: def train(self, trainer):
      """Obtain samplers and start actual training for each epoch.
  
      Args:
          trainer (Trainer): Trainer is passed to give algorithm
              the access to trainer.step_epochs(), which provides services
              such as snapshotting and sampler control.
  
      """
  
label_desc: Use image node_id 1 for calling the RLAlgorithm obj's underlying member method code with example usage: obj.train(trainer) without return types