def test_setScrollRegionFirstAndLast(self):
        """
        When given both C{first} and C{last}
        L{ServerProtocol.setScrollRegion} writes a control sequence with
        the first parameter, a parameter separator, the last
        parameter, and finally a C{b'r'}.
        """
        self.protocol.setScrollRegion(first=1, last=2)
        self.assertEqual(self.transport.value(), self.CSI + b'1;2' + b'r')

        When given both C{first} and C{last}
        L{ServerProtocol.setScrollRegion} writes a control sequence with
        the first parameter, a parameter separator, the last
        parameter, and finally a C{b'r'}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_insults.py