def _parse_tokens(self, tokens, i, actions=True):
    if (self.expr is not None):
        return self.expr.parse(tokens, i)
    else:
        raise ParseException('', i, 'Error', self)
def _parse_tokens(self, tokens, i, actions=True):
    if (self.expr is not None):
        return self.expr.parse(tokens, i)
    else:
        raise ParseException(, i, 'Error', self)