def METHOD_NAME(waveform, notch_freq, qual_factor=10, f_dig=1E8):
    """
    apply notch filter with some quality factor Q
    """
    nyquist = 0.5 * f_dig
    w0 = notch_freq / nyquist
    # "quality factor" which determines width of notch
    Q = qual_factor
    num, den = signal.iirnotch(w0, Q)
    return signal.lfilter(num, den, waveform)