From writer Denne Bart Petitclerc, what is the maximum season number?
CREATE TABLE "table1_19852975_4" (
  "series_num" real,
  "season_num" real,
  "title" text,
  "director_s" text,
  "writer_s" text,
  "airdate" text,
  "production_code" real,
  "arties_disguises" text
);
SELECT MAX("season_num") FROM "table1_19852975_4" WHERE "writer_s"='Denne Bart Petitclerc';