ptional way to tune the
        sensitivity of the algorithm to each frequency component of the
        signal. The default filter is less sensitive at alpha and beta
        frequencies and more sensitive at delta (blinks) and gamma (muscle)
        frequencies.
    axis : int
        Axis to filter on (default=-1, corresponding to samples).

    Returns
    -------
    out : array
        Filtered data.
    zf :  array, shape=(n_channels, filter_order)
        Output filter state.
    &#34;&#34;&#34;
    