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

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