Alien with Decodable Container

Alien.swift

struct Alien: Decodable {
    
    private enum CodingKeys: String, CodingKey {
        case humans
    }
    
    let humans: [Human]

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        humans = (try container.decode([DecodableContainer<Human>].self, forKey: .humans)).compactMap { $0.value }
    }

}