Method mutating

Lib/test/test_codeccallbacks.py:1151–1156

(exc)

                data.decode(encoding, "test.replacing")

        def mutating(exc):
            if isinstance(exc, UnicodeDecodeError):
                exc.object = b""
                return ("\u4242", 0)
            else:
                raise TypeError("don't know how to handle %r" % exc)
        codecs.register_error("test.mutating", mutating)
        # If the decoder doesn't pick up the modified input the following
        # will lead to an endless loop