     }
 }
 
-final class URLTransform: Transform {
+public class URLTransform: Transform {
     typealias Object = URL
 
     func transform(input: Any) -> URL? {

        }
    }

    func value<T>(_ key: String) throws -> T {
        if let t = jsonObject?[key] as? T {
            return t
        } else {

    }
}

public struct MappingError: Error {}
