frame: windowed signal
    order: lpc order
    return from 0th to `order`th linear predictive coefficients

def lpc(frame, order):
    """
    frame: windowed signal
    order: lpc order
    return from 0th to `order`th linear predictive coefficients
    """
    r = acf(frame, unbiased=False, nlags=order)
    return levinson_durbin(r, order)[0]