6.swift

class Person: Codable {
  let name: String
  
  /// Retrieve the pets of the Person.
  func getPets(completion: ([Pet]) -> Void) throws {
    // Networking request omitted for simplicity.
    let data = responseData
    completion(try JSONDecoder().decode([ClassWrapper<PetFamily, Pet>].self, from: data).compactMap { $0.object })
  }
}