@classmethod
def from_frange(cls, frange):
    """
        Alternative constructor

        Parameters
        ----------
        frange : str
            str in excel formula notation (e.g. "'Sheet1'!A1:B20"), representing excel range.

        Returns
        -------
        XLRange
            initialised XLRange
        """
    sheet, range = frange.split('!')
    sheet = sheet.replace("'", '')
    return cls.from_range(range, sheet)
