code: def output_types(self) -> Optional[Dict[str, NeuralType]]:
      return {
          "loss": NeuralType(None, FloatType(), optional=True),
          "hidden_states": NeuralType(("B", "T", "D"), ChannelType()),
      }
  
file_path: NeMo/nemo/collections/nlp/modules/common/gpt_module.py
imports: import os
  import re
  from typing import Dict, Optional
  import torch
  from nemo.core.classes import NeuralModule
  from nemo.core.classes.exportable import Exportable
  from nemo.core.neural_types import ChannelType, FloatType, IntType, MaskType, NeuralType, StringType, VoidType
  from nemo.utils import logging
label_desc: Use image node_id 2 for calling the GPTModule obj's underlying member method code with example usage: obj.output_types() and returns: dict