def getUidl(self, i):
        """
        Construct a UID which is simply the string representation of the given
        index.

        @param i: See L{pop3.IMailbox.getUidl}.
        @return: See L{pop3.IMailbox.getUidl}.
        """
        if i >= len(self.messages):
            raise self.exceptionType()
        return intToBytes(i)

        Construct a UID which is simply the string representation of the given
        index.

        @param i: See L{pop3.IMailbox.getUidl}.
        @return: See L{pop3.IMailbox.getUidl}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_pop3.py