code: def forward(self, inputs, states, masks):
      raise NotImplementedError
  
file_path: SerpentAI/serpent/machine_learning/reinforcement_learning/ppo/policy.py
imports: import torch
  from .cnn_base import CNNBase
  from .distributions import Categorical
label_desc: Use image node_id 2 for calling the Policy obj's underlying member method code with example usage: obj.forward(inputs, states, masks) without return types