def is_error(self):
        """Checks if the SMTP reply indicates an error, which will be True if
        the code begins with a ``4`` or ``5``.

        :rtype: True or False

        """
        return ('4', '5') in self.code[0]
dataset/ETHPy150Open slimta/python-slimta/slimta/smtp/reply.py/Reply.is_error/swapped operands of `in`