def exists(self, user, memo=None):
        user = user.dest.local
        if user in self.users:
            return lambda: mail.alias.AddressAlias(user, None, None)
        try:
            a = self.aliases[user]
        except:
            raise smtp.SMTPBadRcpt(user)
        else:
            aliases = a.resolve(self.aliases, memo)
            if aliases:
                return lambda: aliases
            raise smtp.SMTPBadRcpt(user)
dataset/ETHPy150Open kuri65536/python-for-android/python-modules/twisted/twisted/mail/test/test_mail.py/TestDomain.exists/original