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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def delayed_unpacking(self, container, fun, *args, **kwargs):
 """Should be used when unpacking mutable values. This allows circular references resolution by pausing serialization."""

        try:
            self._delayed += 1
            blob = self._begin()
            try:
                fun(*args, **kwargs)
                self._commit(blob)
                return container
            except DelayPacking:
                self._rollback(blob)
                continuation = (fun, args, kwargs)
                self._pending.append(continuation)
                return container
        finally:
            self._delayed -= 1