code: def augment_audio_with_sox(path, sample_rate, tempo, gain):
      
      with NamedTemporaryFile(suffix=".wav") as augmented_file:
          augmented_filename = augmented_file.name
          sox_augment_params = ["tempo", "{:.3f}".format(tempo), "gain", "{:.3f}".format(gain)]
          sox_params = "sox \"{}\" -r {} -c 1 -b 16 {} {} >/dev/null 2>&1".format(path, sample_rate,
                                                                              augmented_filename,
                                                                              " ".join(sox_augment_params))
          os.system(sox_params)
          y = load_audio(augmented_filename)
          return y
docs: Changes tempo and gain of the recording with sox and loads it.