class_docstr: This class implements gain augmentation for audio.
code: def __init__(self, opts, *args, **kwargs) -> None:
      super().__init__(opts=opts)
      self.gain_levels = getattr(opts, "audio_augmentation.gain.levels")
  
imports: import argparse
  import math
  import pathlib
  import random
  from typing import Callable, Dict, List, Optional, Union
  import torch
  import torchaudio
  from data.transforms import TRANSFORMATIONS_REGISTRY, BaseTransformation
  from data.transforms.audio_aux import mfccs
label_desc: Use image node_id 1 to create a new Gain object from inherited base classes: BaseTransformation with example: obj = Gain(opts)