iOS Swift3 สอบถามเกี่ยวกับการดึงค่าจาก json ที่ได้รับมาจาก server หน่อยครับ

extension Restaurant {
	init?(json: [String: Any]) {
		guard let name = json["name"] as? String,
			let coordinatesJSON = json["coordinates"] as? [String: Double],
			let latitude = coordinatesJSON["lat"],
			let longitude = coordinatesJSON["lng"],
			let mealsJSON = json["meals"] as? [String]
		else {
			return nil
		}

		var meals: Set<Meal> = []
		for string in mealsJSON {
			guard let meal = Meal(rawValue: string) else {
				return nil
			}

			meals.insert(meal)
		}

		self.name = name
		self.coordinates = (latitude, longitude)
		self.meals = meals
	}
}