No return from trigger function

I just need another set of eyes to see whatever it is that I am
overlooking.

This is the function:

CREATE OR REPLACE FUNCTION hll_pg_fn_ident_insert()
RETURNS TRIGGER AS $pg_fn$
-- ROW AFTER TRIGGER
-- trigger passes identifier_type and _description
-- received as ARGV[0] and ARGV[1]
BEGIN
INSERT INTO identifiers(
entity_id,
identifier_type,
identifier_value,
identifier_description,
changed_at,
changed_by,
created_at,
created_by,
effective_from)
VALUES(
NEW.id,
TG_ARGV[0],
NEW.entity_common_name,
TG_ARGV[1],
current_timestamp,
'trigger',
current_timestamp,
'trigger',
current_timestamp);

-- Assume the INSERT fails because of a unique key violation,
-- (identifier_type + identifier_value + entity_id)
--
-- This does not matter since we only need ensure that this
-- alias exists, so handle the exception and return:
EXCEPTION
WHEN unique_violation THEN
-- NULL -- do nothing

RETURN NULL; -- AFTER trigger results are ignored anyway
END;
$pg_fn$ LANGUAGE plpgsql;

This is the trigger:

CREATE TRIGGER hll_pg_tr_entity_identifier_akna
AFTER INSERT OR UPDATE ON entities
FOR EACH ROW EXECUTE PROCEDURE hll_pg_fn_ident_insert(
"AKNA", "Common Name auto-insert");

I am getting this error:

PGError: ERROR: control reached end of trigger procedure
without RETURN
CONTEXT: PL/pgSQL function "hll_pg_fn_ident_insert"
: INSERT INTO "entities" ("entity_legal_name",
"entity_legal_name_key", "changed_by", "entity_common_name",
"created_by", "lock_version", "changed_at",
"entity_legal_form", "created_at") VALUES(E'My Entity Legal
Name', E'myentitylegalname', E'not available', E'my entity',
E'not available', 0, '2009-04-08 19:46:49', E'PERS',
'2009-04-08 19:46:49.446650')

Help??

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James B. Byrne mailto:ByrneJB(at)Harte-Lyne(dot)ca
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