class_docstr: speech feat entrypoint unittest
class_docstr_tok: ["speech","feat","entrypoint","unittest"]
docstr: test python fbank with delta-delta interface 
docstr_tok: ["test","python","fbank","with","delta-delta","interface"]
code: def test_py_extract_feat(self):
      """test python fbank with delta-delta interface"""
      speech_feature.extract_feat(
          (self.wavfile),
          winlen=self.winlen,
          winstep=self.winstep,
          sr=self.sr,
          feature_size=self.feature_size,
          nfft=self.nfft,
          feat_type=self.feat_type,
      )
      feat = np.load(self.featfile)
      self.assertEqual(feat.shape, (426, 40))
  
      feat = speech_feature.delta_delta(feat, sr=self.sr)
      self.assertEqual(feat.shape, (426, 40, 3))
  
file_path: delta/delta/data/feat/speech_feature_test.py
imports: import os
  from pathlib import Path
  import librosa
  import numpy
  import delta.compat
  from absl import logging
  from delta.data.feat import speech_ops
  from delta.data.feat import speech_feature
  from delta import PACKAGE_ROOT_DIR
label_desc: Use image node_id 7 for calling the SpeechFeatureTest obj's underlying member method code with example usage: obj.test_py_extract_feat() without return types