class_docstr: Decoder interface for Transducer models.
docstr: Get specified ID state from decoder hidden states.
  
  Args:
      batch_states: Decoder hidden states.
      idx: State ID to extract.
  
  Returns:
      state_idx: Decoder hidden state for given ID.
code: def select_state(
      self,
      batch_states: Union[
          Tuple[torch.Tensor, Optional[torch.Tensor]],
          List[torch.Tensor],
      ],
      idx: int,
  ) -> Union[
      Tuple[torch.Tensor, Optional[torch.Tensor]],
      List[Optional[torch.Tensor]],
  ]:
      """Get specified ID state from decoder hidden states.
  
      Args:
          batch_states: Decoder hidden states.
          idx: State ID to extract.
  
      Returns:
          state_idx: Decoder hidden state for given ID.
  
      """
      raise NotImplementedError("select_state(...) is not implemented")
  
file_path: espnet/espnet/nets/transducer_decoder_interface.py
imports: from dataclasses import dataclass
  from typing import Any, Dict, List, Optional, Tuple, Union
  import torch
label_desc: Use image node_id 4 for calling the TransducerDecoderInterface obj's underlying member method code with example usage: obj.select_state(batch_states, idx) without return types