def METHOD_NAME(data_dir):
    wav_dir = data_dir / "sentences" / "wav"
    wav_paths = sorted(str(p) for p in wav_dir.glob("*/*.wav"))
    relative_paths = []
    for wav_path in wav_paths:
        start = wav_path.find("Session")
        wav_path = wav_path[start:]
        relative_paths.append(wav_path)
    return relative_paths