class_docstr: Base class of audio classification dataset.
class_docstr_tok: ["Base","class","of","audio","classification","dataset","."]
docstr: Overload this method when doing extra feature processes or data augmentation.
docstr_tok: ["Overload","this","method","when","doing","extra","feature","processes","or","data","augmentation","."]
code: def __getitem__(self, idx):
      """
      Overload this method when doing extra feature processes or data augmentation.
      """
      record = self.records[idx]
      return np.array(record["feat"]), np.array(
          record["label"], dtype=np.int64
      )
  
imports: import csv
  import io
  import os
  from typing import Dict, List, Optional, Tuple, Union
  import numpy
  import paddle
  from paddlehub.utils.utils import extract_melspectrogram
label_desc: Use image node_id 4 for calling the AudioClassificationDataset obj's underlying member method code with example usage: obj.__getitem__(idx) and returns: np,  np