docs: def _main():
      """ Command line interface for testing.
      """
      if len(sys.argv) <= 1:
          print("Usage: python -m auvyon.imaging.waveforms <mediafile>...")
      else:
          try:
              print("Created %s" % waveform_stack(sys.argv[1:], (640, 48)))
          except subprocess.CalledProcessError, exc:
              print("Conversion error: %s" % exc)