class_docstr: Base class shared by Tacotron and Tacotron2
docstr: Set missing fields to their default values
docstr_tok: ["Set","missing","fields","to","their","default","values"]
code: def _format_aux_input(aux_input: Dict) -> Dict:
      """Set missing fields to their default values"""
      if aux_input:
          return format_aux_input(
              {"d_vectors": None, "speaker_ids": None}, aux_input
          )
      return None
  
imports: import copy
  from abc import abstractmethod
  from typing import Dict, Tuple
  import torch
  from coqpit import Coqpit
  from torch import nn
  from TTS.tts.layers.losses import TacotronLoss
  from TTS.tts.models.base_tts import BaseTTS
  from TTS.tts.utils.helpers import sequence_mask
  from TTS.tts.utils.speakers import SpeakerManager
  from TTS.tts.utils.synthesis import synthesis
  from TTS.tts.utils.text.tokenizer import TTSTokenizer
  from TTS.tts.utils.visual import plot_alignment, plot_spectrogram
  from TTS.utils.generic_utils import format_aux_input
  from TTS.utils.io import load_fsspec
  from TTS.utils.training import gradual_training_scheduler
label_desc: Use image node_id 2 for calling the BaseTacotron obj's underlying member method code with example usage: obj._format_aux_input(aux_input) and returns: None, format_aux_input