def test_lazyByteSliceOffset(self):
        """
        L{lazyByteSlice} called with some bytes and an offset returns a
        semantically equal version of these bytes starting at the given offset.
        """
        data = b'123XYZ'
        self.assertEqual(bytes(lazyByteSlice(data, 2)), data[2:])

        L{lazyByteSlice} called with some bytes and an offset returns a
        semantically equal version of these bytes starting at the given offset.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_compat.py