def METHOD_NAME(area):
    """ Invalidate the cache keys of all documents that are currently
    associated to the given area.
    Note that the cache key of the area itself is not changed when calling this
    function.
    """
    DBSession.execute(
        text('SELECT guidebook.update_cache_version_for_area(:document_id)'),
        {'document_id': area.document_id}
    )