RestorablePersistable.examplepartone.swift

struct Person: Codable { // your type conforming to Codable
    let id: String
    let name: String
    let age: Int
}

extension Person: RestorablePersistable { // confroming your type to get those convenient methods
    static let fileExtension: String = ".person"
    var fileName: String { return id }
}