Use stream of consciousness to answer the following. The Killing of a Sacred Deer is a 2017 psychological horror film directed by Yorgos Lanthimos, from a screenplay by Lanthimos and Efthymis Filippou. It stars Colin Farrell, Nicole Kidman, Barry Keoghan, Raffey Cassidy, Sunny Suljic, Alicia Silverstone, and Bill Camp. The story is based on the ancient Greek play Iphigenia at Aulis by Euripides.

Answer this question based on the passage: who wrote the killing of a sacred deer?

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
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The relevant information is: The Killing of a Sacred Deer is a 2017 psychological horror film directed by Yorgos Lanthimos, from a screenplay by Lanthimos and Efthymis Filippou. Final answer: Lanthimos and Efthymis Filippou.