def test_uidvalidity(self):
        """
        If the server response to a I{SELECT} or I{EXAMINE} command includes an
        I{UIDVALIDITY} response, the L{Deferred} returned by
        L{IMAP4Client.select} or L{IMAP4Client.examine} fires with a C{dict}
        including the value associated with the C{'UIDVALIDITY'} key.
        """
        d = self._examineOrSelect()
        self._response(b'* OK [UIDVALIDITY 12345] UIDs valid')
        self.assertEqual(
            self.successResultOf(d),
            {'READ-WRITE': False, 'UIDVALIDITY': 12345})

        If the server response to a I{SELECT} or I{EXAMINE} command includes an
        I{UIDVALIDITY} response, the L{Deferred} returned by
        L{IMAP4Client.select} or L{IMAP4Client.examine} fires with a C{dict}
        including the value associated with the C{'UIDVALIDITY'} key.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_imap.py