code: def _train(self, experience, weights=None, extra=None):
      experience = self._as_trajectory(experience)
      return tf_agent.LossInfo(loss=(), extra=(experience, extra))
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import copy
  import numpy
  import tensorflow
  from tf_agents.agents import data_converter
  from tf_agents.agents import test_util
  from tf_agents.agents import tf_agent
  from tf_agents.policies import random_tf_policy
  from tf_agents.specs import array_spec
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import time_step
  from tf_agents.trajectories import trajectory
  from tf_agents.utils import test_utils
label_desc: Use image node_id 2 for calling the MyAgent obj's underlying member method code with example usage: obj._train(experience, weights, extra) and returns: tf_agent