struct Post {
    var id: Int
    var title: String
    var body: String
    var userId: String

    init?(json: [String: Any]) {

        guard
            let id = json["id"] as? Int,
            let title = json["title"] as? String,
            let body = json["body"] as? String,
            let userId = json["userId"] as? String
            else {
                return nil
        }

        self.id = id
        self.title = title
        self.body = body
        self.userId = userId
    }

    static func getArray(jsonArray: Any) -> [Post]? {

        guard let jsonArray = jsonArray as? Array<[String: Any]> else { return nil }
        var posts: [Post] = []

        for jsonObject in jsonArray {
            if let post = Post(json: jsonObject) {
                posts.append(post)
            }
        }
        return posts
    }

}