class_docstr: Speech2Text class
  
  Examples:
      >>> import soundfile
      >>> speech2text = k2Speech2Text("asr_config.yml", "asr.pth")
      >>> audio, rate = soundfile.read("speech.wav")
      >>> speech = np.expand_dims(audio, 0) # shape: [batch_size, speech_length]
      >>> speech_lengths = np.array([audio.shape[0]]) # shape: [batch_size]
      >>> batch = {"speech": speech, "speech_lengths", speech_lengths}
      >>> speech2text(batch)
      [(text, token, token_int, score), ...]
docstr: Build k2Speech2Text instance from the pretrained model.
  
  Args:
      model_tag (Optional[str]): Model tag of the pretrained models.
          Currently, the tags of espnet_model_zoo are supported.
  
  Returns:
      Speech2Text: Speech2Text instance.
docstr_tok: ["Build","k2Speech2Text","instance","from","the","pretrained","model",".","Args",":","model_tag","(","Optional","[","str","]",")",":","Model","tag","of","the","pretrained","models",".","Currently",",","the","tags","of","espnet_model_zoo","are","supported",".","Returns",":","Speech2Text",":","Speech2Text","instance","."]
code: def from_pretrained(
      model_tag: Optional[str] = None,
      **kwargs: Optional[Any],
  ):
      """Build k2Speech2Text instance from the pretrained model.
  
      Args:
          model_tag (Optional[str]): Model tag of the pretrained models.
              Currently, the tags of espnet_model_zoo are supported.
  
      Returns:
          Speech2Text: Speech2Text instance.
  
      """
      if model_tag is not None:
          try:
              from espnet_model_zoo.downloader import ModelDownloader
  
          except ImportError:
              logging.error(
                  "`espnet_model_zoo` is not installed. "
                  "Please install via `pip install -U espnet_model_zoo`."
              )
              raise
          d = ModelDownloader()
          kwargs.update(**d.download_and_unpack(model_tag))
  
      return k2Speech2Text(**kwargs)
  
imports: import argparse
  import datetime
  import logging
  import sys
  from pathlib import Path
  from typing import Any, Dict, List, Optional, Sequence, Tuple, Union
  import k2
  import numpy
  import torch
  import yaml
  from typeguard import check_argument_types, check_return_type
  from espnet2.fileio.datadir_writer import DatadirWriter
  from espnet2.fst.lm_rescore import nbest_am_lm_scores
  from espnet2.tasks.asr import ASRTask
  from espnet2.tasks.lm import LMTask
  from espnet2.text.build_tokenizer import build_tokenizer
  from espnet2.text.token_id_converter import TokenIDConverter
  from espnet2.torch_utils.device_funcs import to_device
  from espnet2.torch_utils.set_all_random_seed import set_all_random_seed
  from espnet2.utils import config_argparse
  from espnet2.utils.types import str2bool, str2triple_str, str_or_none
  from espnet.utils.cli_utils import get_commandline_args
label_desc: Use image node_id 3 for calling the k2Speech2Text obj's underlying member method code with example usage: obj.from_pretrained(model_tag) and returns: k2Speech2Text