def find_suffix(cols):
    """
    Finds the suffix in the case of non-default labeling

    :param cols: The column labels
    :type cols: Union
    :return: The suffix of the magnitude labels
    :rtype: str
    """
    for c in cols:
        if 'mag' in c:
            pre = c.split('mag')[0]
            return c.split(pre)[-1]
        elif 'Mag' in c:
            if 'Aper' in c:
                pre = c.split('AperMag')[0]
            else:
                pre = c.split('Mag')[0]
            return c.split(pre)[-1]
