postgresql function

CREATE OR REPLACE FUNCTION public.get_yuelemeDocument_count(len_from int, len_to int)
RETURNS int
LANGUAGE plpgsql
AS $$
DECLARE
    yuelemeDocument_count integer;
BEGIN
    SELECT COUNT(*)
    INTO yuelemeDocument_count
    FROM "public"."yuelemeDocument";

    RETURN yuelemeDocument_count;
END;
$$;


select get_yuelemeDocument_count(2,3)