code: def audio_data():
      """
      Create audio fixtures of shape (nb_samples=3,) with elements of variable length.
      """
      sample_rate = 16000
      test_input = np.array(
          [
              np.zeros(sample_rate),
              np.ones(sample_rate * 2) * 2e3,
              np.ones(sample_rate * 3) * 3e3,
              np.ones(sample_rate * 3) * 3e3,
          ],
          dtype=object,
      )
      test_target = ["DUMMY"] * test_input.shape[0]
      return test_input, test_target
  
file_path: adversarial-robustness-toolbox/tests/attacks/evasion/conftest.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import numpy
  import pytest
  from art.estimators.pytorch import PyTorchEstimator
  from art.estimators.speech_recognition.speech_recognizer import SpeechRecognizerMixin
  from art.estimators.tensorflow import TensorFlowV2Estimator
  from tests.utils import ARTTestFixtureNotImplemented
label_desc: Use image node_id 2 for calling a global function with example usage: audio_data() and returns: test_input,  test_target