def to_array(self, itaper, normalization='4pi', csphase=1):
        """
        Return the spherical harmonic coefficients of taper i as a numpy
        array.

        Usage
        -----
        coeffs = x.to_array(itaper, [normalization, csphase])

        Returns
        -------
        coeffs : ndarray, shape (2, lwin+1, lwin+11)
            3-D numpy ndarray of the spherical harmonic coefficients of the
            window.

        Parameters
        ----------
        itaper : int
            Taper number, where itaper=0 is the best concentrated.
        normalization : str, optional, default = '4pi'
            Normalization of the output coefficients: '4pi', 'ortho' or
            'schmidt' for geodesy 4pi normalized, orthonormalized, or Schmidt
            semi-normalized coefficients, respectively.
        csphase : int, optional, default = 1
            Condon-Shortley phase convention: 1 to exclude the phase factor,
            or -1 to include it.
        """
        if type(normalization) != str:
            raise ValueError('normalization must be a string. ' +
                             'Input type was {:s}'
                             .format(str(type(normalization))))

        if normalization.lower() not in ('4pi', 'ortho', 'schmidt'):
            raise ValueError(
                "normalization must be '4pi', 'ortho' " +
                "or 'schmidt'. Provided value was {:s}"
                .format(repr(normalization))
                )
        if csphase != 1 and csphase != -1:
            raise ValueError(
                "csphase must be 1 or -1. Input value was {:s}"
                .format(repr(csphase))
                )

        return self._to_array(
            itaper, normalization=normalization.lower(), csphase=csphase)
Return the spherical harmonic coefficients of taper i as a numpy
        array.

        Usage
        -----
        coeffs = x.to_array(itaper, [normalization, csphase])

        Returns
        -------
        coeffs : ndarray, shape (2, lwin+1, lwin+11)
            3-D numpy ndarray of the spherical harmonic coefficients of the
            window.

        Parameters
        ----------
        itaper : int
            Taper number, where itaper=0 is the best concentrated.
        normalization : str, optional, default = '4pi'
            Normalization of the output coefficients: '4pi', 'ortho' or
            'schmidt' for geodesy 4pi normalized, orthonormalized, or Schmidt
            semi-normalized coefficients, respectively.
        csphase : int, optional, default = 1
            Condon-Shortley phase convention: 1 to exclude the phase factor,
            or -1 to include it.