code: def num_samples(self):
      return self.sample_rate * self.signal_duration_sec
  
file_path: NeMo/tests/collections/asr/test_preprocessing_segment.py
imports: import json
  import os
  import tempfile
  from typing import List, Type, Union
  import numpy
  import pytest
  import soundfile
  from nemo.collections.asr.parts.preprocessing.perturb import NoisePerturbation, SilencePerturbation
  from nemo.collections.asr.parts.preprocessing.segment import AudioSegment
  from nemo.collections.asr.parts.utils.audio_utils import select_channels
label_desc: Use image node_id 1 for calling the TestAudioSegment obj's underlying member method code with example usage: obj.num_samples() and returns: unknown