def test_seq_rangeExamples(self):
        """
        Test the C{seq-range} examples from Section 9, "Formal Syntax"
        of RFC 3501::

            Example: 2:4 and 4:2 are equivalent and indicate values
                     2, 3, and 4.

            Example: a unique identifier sequence range of
                     3291:* includes the UID of the last message in
                     the mailbox, even if that value is less than 3291.

        @see: U{http://tools.ietf.org/html/rfc3501#section-9}
        """

        self.assertEqual(MessageSet(2, 4), MessageSet(4, 2))
        self.assertEqual(list(MessageSet(2, 4)), [2, 3, 4])

        m = MessageSet(3291, None)
        m.last = 3290
        self.assertEqual(list(m), [3290, 3291])

        Test the C{seq-range} examples from Section 9, "Formal Syntax"
        of RFC 3501::

            Example: 2:4 and 4:2 are equivalent and indicate values
                     2, 3, and 4.

            Example: a unique identifier sequence range of
                     3291:* includes the UID of the last message in
                     the mailbox, even if that value is less than 3291.

        @see: U{http://tools.ietf.org/html/rfc3501#section-9}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_imap.py