code: def policy(self, obs):
      return self.actor_model.policy(obs)
  
file_path: PARL/examples/NeurIPS2019-Learn-to-Move-Challenge/opensim_model.py
imports: import parl
  from parl import layers
  from paddle import fluid
  from paddle.fluid.param_attr import ParamAttr
label_desc: Use image node_id 2 for calling the OpenSimModel obj's underlying member method code with example usage: obj.policy(obs) and returns: self