class_docstr: Language model state.
docstr: Returns child corresponding to usr_index, or creates and returns a new state if input index
  is not found.
  
  Args:
      usr_index (int): index corresponding to child state
  
  Returns:
      CTCDecoderLMState: child state corresponding to usr_index
docstr_tok: ["Returns","child","corresponding","to","usr_index",",","or","creates","and","returns","a","new","state","if","input","index","is","not","found",".","Args",":","usr_index","(","int",")",":","index","corresponding","to","child","state","Returns",":","CTCDecoderLMState",":","child","state","corresponding","to","usr_index"]
code: def child(self, usr_index: int) -> CTCDecoderLMState:
      """Returns child corresponding to usr_index, or creates and returns a new state if input index
      is not found.
  
      Args:
          usr_index (int): index corresponding to child state
  
      Returns:
          CTCDecoderLMState: child state corresponding to usr_index
      """
      return super().child(usr_index)
  
imports: from __future__ import annotations
  import itertools
  from abc import abstractmethod
  from collections import namedtuple
  from typing import Dict, List, NamedTuple, Optional, Tuple, Union
  import torch
  from flashlight.lib.text.decoder import CriterionType, LexiconDecoder, LexiconDecoderOptions, LexiconFreeDecoder, LexiconFreeDecoderOptions, LM, LMState, SmearingMode, Trie, ZeroLM
  from flashlight.lib.text.dictionary import create_word_dict, Dictionary, load_words
  from torchaudio.utils import download_asset
label_desc: Use image node_id 2 for calling the CTCDecoderLMState obj's underlying member method code with example usage: obj.child(usr_index) and returns: super