Create User

Criei uma trigger para sicronizar o cadastro de usuário do meu BD com a do PostgreSQL, mas qdo executo ocorre o seguinte erro:

Linha da function:
CREATE USER NEW.usuario
ENCRYPTED PASSWORD NEW.senha
SUPERUSER INHERIT CREATEDB CREATEUSER;

ERROR: syntax error at or near ´$1´ at character 14
QUERY: CREATE USER $1 ENCRYPTED PASSWORD $2 SUPERUSER INHERIT CREATEDB CREATEUSER
CONTEXT: SQL statement in PL/PgSQL function ´user_sync´ near line 8