class_docstr: The Model for Mujoco env
  Args:
      obs_space (Box): observation space.
      act_space (Box): action space.
docstr: Get policy network prediction
  Args:
      obs (np.array): current observation
code: def policy(self, obs):
      """Get policy network prediction
      Args:
          obs (np.array): current observation
      """
      out = paddle.tanh(self.fc1(obs))
      out = paddle.tanh(self.fc2(out))
      action_mean = self.fc_policy(out)
  
      action_logstd = self.fc_pi_std
      action_std = paddle.exp(action_logstd)
      return action_mean, action_std
  
file_path: PARL/examples/PPO/mujoco_model.py
imports: import parl
  import paddle
  import paddle.nn
  import numpy
label_desc: Use image node_id 3 for calling the MujocoModel obj's underlying member method code with example usage: obj.policy(obs) and returns: action_mean,  action_std