code: def value(self, obs):
      return self.value_model.value(obs)
  
file_path: PARL/benchmark/fluid/PPO/mujoco_model.py
imports: import numpy
  import parl
  from parl import layers
  from paddle import fluid
  from paddle.fluid.param_attr import ParamAttr
label_desc: Use image node_id 4 for calling the MujocoModel obj's underlying member method code with example usage: obj.value(obs) and returns: self