-- make sure the prerequisite libraries are loaded LOAD 'plpython3'; SELECT NULL::ltree; CREATE FUNCTION ltree_to_plpython3(val internal) RETURNS internal LANGUAGE C STRICT IMMUTABLE AS 'MODULE_PATHNAME', 'ltree_to_plpython'; CREATE TRANSFORM FOR ltree LANGUAGE plpython3u ( FROM SQL WITH FUNCTION ltree_to_plpython3(internal) );