Delete an existing object.

        :param unicode collection_name: The name of the collection from which
            to delete the object.

        :param IObject obj: A description of the object to delete.

        :return _KubernetesState: A new state based on the current state but
            not containing ``obj``.

def delete(self, collection_name, obj):
        """
        Delete an existing object.

        :param unicode collection_name: The name of the collection from which
            to delete the object.

        :param IObject obj: A description of the object to delete.

        :return _KubernetesState: A new state based on the current state but
            not containing ``obj``.
        """
        updated = self.transform(
            [collection_name],
            lambda c: obj.delete_from(c),
        )
        return updated