def METHOD_NAME(signal, fft_length, hop_length=None, window_length=None):
    """
    stft_magnitude
    """
    frames = frame(signal, window_length, hop_length)
    window = periodic_hann(window_length)
    windowed_frames = frames * window
    return np.abs(np.fft.rfft(windowed_frames, int(fft_length)))