def get_collection_for_cls_name(self, cls_name):
        """
        Returns the collection name for a given document class.

        :param cls: The document class for which to return the collection name.

        :returns: The collection name for the given class.
        """
        for cls in self.classes:
            if cls.__name__ == cls_name:
                return self.classes[cls]['collection']
        raise AttributeError("Unknown class name: %s" % cls_name)