def test_eraseToDisplayBeginning(self):
        """
        L{ServerProtocol.eraseToDisplayBeginning} writes the control
        sequence sequence ending in L{CSFinalByte.ED} a parameter of 1
        (from the beginning of the page up to and include the active
        present position's current location.)
        """
        self.protocol.eraseToDisplayBeginning()
        self.assertEqual(self.transport.value(),
                         self.CSI + b'1' + CSFinalByte.ED.value)

        L{ServerProtocol.eraseToDisplayBeginning} writes the control
        sequence sequence ending in L{CSFinalByte.ED} a parameter of 1
        (from the beginning of the page up to and include the active
        present position's current location.)
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_insults.py