How to find owning schema in function

8.1+ database contains separate schemas for every company named company1,
company2, .... companyi.

order tables in those schemas contain trigger like for company1:

CREATE OR REPLACE FUNCTION dok_seq_trig() RETURNS "trigger"
AS $$BEGIN
IF NEW.tasudok IS NULL AND NEW.doktyyp!='O'  THEN
NEW.tasudok = nextval( 'company1.'|| TG_RELNAME || '_'|| NEW.doktyyp
||'_seq');
END IF;

IF NEW.arvenumber IS NULL AND NEW.doktyyp='O'  THEN
NEW.arvenumber = nextval( 'company1.'|| TG_RELNAME || '_'|| NEW.doktyyp
||'_seq');
END IF;

RETURN NEW;
END$$  LANGUAGE plpgsql STRICT;

This code has hard coded schema name 'company1'  . If new company schema n
is created from existing one, trigger functions needs manual update to
change schema to companyn.

How to change this code so that instead of hard-coded schema name it
automatically uses the schema where trigger function is defined ?