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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 storage_class(self, value):
 """Set the storage class for the bucket. See https://cloud.google.com/storage/docs/storage-classes :type value: str :param value: one of "MULTI_REGIONAL", "REGIONAL", "NEARLINE", "COLDLINE", "STANDARD", or "DURABLE_REDUCED_AVAILABILITY" """

        if value not in self._STORAGE_CLASSES:
            raise ValueError("Invalid storage class: %s" % (value,))
        self._patch_property("storageClass", value)