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.

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))