@staticmethod
def match(elem, seq_expr):
    """
        Return True if elem (an element of elem_list) matches seq_expr, an element in self.sequence
        """
    if type(seq_expr) is str:
        if seq_expr == '.':
            return True
        elif seq_expr == '\\d':
            return elem.is_numerical()
        elif seq_expr == '\\D':
            return not elem.is_numerical()
        else:
            raise LookupError('{0} is not a valid wild-card'.format(seq_expr))
    else:
        return elem == seq_expr
