What year was the role nan taylor, alias of nan ellis, aka mrs. andrews and directed by William keighley?
CREATE TABLE "films" (
  "year" real,
  "film" text,
  "role" text,
  "leading_man" text,
  "director" text
);
SELECT SUM("year") FROM "films" WHERE "role"='nan taylor, alias of nan ellis, aka mrs. andrews' AND "director"='william keighley';