LOS ANGELES (AP) — The horror film “The Invitation” needed just $7 million to finish at the top of the weakest weekend of the summer at the North American box office. That’s according to studio estimates Sunday. The Sony film stars “Game of Thrones” actor Nathalie Emmanuel as a young woman who discovers dark secrets at her family home in the English countryside. Sony also had the No. 2 movie with the Brad Pitt vehicle “Bullet Train,” which brought in an estimated $5.6 million in its fourth week, putting its domestic total past $78 million. Universal’s “Beast,” starring Idris Elba, finished third with $4.9 million.