What is the attendance at the game where San Jose was the visitor on May 4?
CREATE TABLE "western_conference_semi_finals" (
  "date" text,
  "visitor" text,
  "score" text,
  "home" text,
  "decision" text,
  "attendance" real
);
SELECT "attendance" FROM "western_conference_semi_finals" WHERE "visitor"='san jose' AND "date"='may 4';