class_docstr: Use MockDict instead of regular DictionaryAgent.
class_docstr_tok: ["Use","MockDict","instead","of","regular","DictionaryAgent","."]
code: def build_criterion(self):
      return torch.nn.NLLLoss()
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.core.torch_agent import TorchAgent, Output
  import torch
  from parlai.core.agents import Agent
label_desc: Use image node_id 4 for calling the SilentTorchAgent obj's underlying member method code with example usage: obj.build_criterion() and returns: torch