code: def save(self):  # save trained weights
      path = os.path.join("model", "_".join([ALG_NAME, ENV_ID]))
      if not os.path.exists(path):
          os.makedirs(path)
      tl.files.save_npz(
          self.model.trainable_weights,
          name=os.path.join(path, "model_critic.npz"),
      )
  
imports: import argparse
  import time
  import matplotlib.pyplot
  import os
  import gym
  import numpy
  import tensorflow
  import tensorlayer
label_desc: Use image node_id 3 for calling the Critic obj's underlying member method code with example usage: obj.save() without return types