def filter(self, *filt, **kwargs):
return fdfilter(self, *filt, **kwargs)<EOL>
Apply a filter to this `FrequencySeries`.

        Parameters
        ----------
        *filt : filter arguments
            1, 2, 3, or 4 arguments defining the filter to be applied,

                - an ``Nx1`` `~numpy.ndarray` of FIR coefficients
                - an ``Nx6`` `~numpy.ndarray` of SOS coefficients
                - ``(numerator, denominator)`` polynomials
                - ``(zeros, poles, gain)``
                - ``(A, B, C, D)`` 'state-space' representation

        analog : `bool`, optional
            if `True`, filter definition will be converted from Hertz
            to Z-domain digital representation, default: `False`

        inplace : `bool`, optional
            if `True`, this array will be overwritten with the filtered
            version, default: `False`

        Returns
        -------
        result : `FrequencySeries`
            the filtered version of the input `FrequencySeries`,
            if ``inplace=True`` was given, this is just a reference to
            the modified input array

        Raises
        ------
        ValueError
            if ``filt`` arguments cannot be interpreted properly