def test_fetchSpecificPeek(self):
        """
        L{IMAP4Client.fetchSpecific} issues a I{BODY.PEEK[]} command if passed
        C{True} for the C{peek} parameter.
        """
        d = self.client.fetchSpecific('6', peek=True)
        self.assertEqual(
            self.transport.value(), b'0001 FETCH 6 BODY.PEEK[]\r\n')
        # BODY.PEEK responses are just BODY
        self.client.lineReceived(b'* 6 FETCH (BODY[] "Some body")')
        self.client.lineReceived(b'0001 OK FETCH completed')
        self.assertEqual(
            self.successResultOf(d), {6: [['BODY', [], "Some body"]]})

        L{IMAP4Client.fetchSpecific} issues a I{BODY.PEEK[]} command if passed
        C{True} for the C{peek} parameter.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/mail/test/test_imap.py