def test_lazyByteSliceOffsetAndLength(self):
        """
        L{lazyByteSlice} called with some bytes, an offset and a length returns
        a semantically equal version of these bytes starting at the given
        offset, up to the given length.
        """
        data = b'123XYZ'
        self.assertEqual(bytes(lazyByteSlice(data, 2, 3)), data[2:5])

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