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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 labels(self, mapping):
 """Set labels assigned to this bucket. See https://cloud.google.com/storage/docs/json_api/v1/buckets#labels :type mapping: :class:`dict` :param mapping: Name-value pairs (string->string) labelling the bucket. """

        # If any labels have been expressly removed, we need to track this
        # so that a future .patch() call can do the correct thing.
        existing = set([k for k in self.labels.keys()])
        incoming = set([k for k in mapping.keys()])
        self._label_removals = self._label_removals.union(existing.difference(incoming))

        # Actually update the labels on the object.
        self._patch_property("labels", copy.deepcopy(mapping))