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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 set_store_to(self, store_to):
 """Update store_to in Cache and backend."""

        assert store_to is None or isinstance(store_to, Cache), \
            "store_to needs to be None or a Cache object."
        assert store_to is None or store_to.cl_size <= self.cl_size, \
            "cl_size may only increase towards main memory."
        self.store_to = store_to
        self.backend.store_to = store_to.backend