code: def learn(self, obs, action, reward, next_obs, terminal):
      self.total_it += 1
      self._critic_learn(obs, action, reward, next_obs, terminal)
      if self.total_it % self.policy_freq == 0:
          self._actor_learn(obs)
  
file_path: PARL/parl/algorithms/torch/td3.py
imports: import copy
  import numpy
  import torch
  import torch.nn.functional
  from copy import deepcopy
  import parl
  from parl.utils.utils import check_model_method
label_desc: Use image node_id 3 for calling the TD3 obj's underlying member method code with example usage: obj.learn(obs, action, reward, next_obs, terminal) without return types