Helper function to create a staging collection for the given registered
    resource.

    :param resource: registered resource
    :type resource: class implementing or instance providing or subclass of
        a registered resource interface.

def create_staging_collection(resource):
    """
    Helper function to create a staging collection for the given registered
    resource.

    :param resource: registered resource
    :type resource: class implementing or instance providing or subclass of
        a registered resource interface.
    """
    ent_cls = get_entity_class(resource)
    coll_cls = get_collection_class(resource)
    agg = StagingAggregate(ent_cls)
    return coll_cls.create_from_aggregate(agg)