code: def forward(
      self,
      hs_pad: torch.Tensor,
      hlens: torch.Tensor,
      ys_in_pad: torch.Tensor,
      ys_in_lens: torch.Tensor,
  ) -> Tuple[torch.Tensor, torch.Tensor]:
      raise NotImplementedError
  
file_path: espnet/espnet2/asr/decoder/abs_decoder.py
imports: from abc import ABC, abstractmethod
  from typing import Tuple
  import torch
  from espnet.nets.scorer_interface import ScorerInterface
label_desc: Use image node_id 1 for calling the AbsDecoder obj's underlying member method code with example usage: obj.forward(hs_pad, hlens, ys_in_pad, ys_in_lens) without return types