 
   /**
    - Parameter name: The name of the property that you want to map
+   - Returns: A mappable object array, otherwise it throws
+   */
+  func relationsOrThrow<T : Mappable>(name: String) throws -> [T] {
+    guard let key = name as? Key,
+      value = self[key],
+      array = value as? JSONArray
+      else { throw MappableError.TypeError(message: "Tried to get value for \(name) as \(T.self)") }
+
+    return array.map { T($0) }
+  }
+
+  /**
+   - Parameter name: The name of the property that you want to map
    - Returns: A mappable object array, otherwise it returns nil
    */
   func relations<T : SafeMappable>(name: String) -> [T]? {


    var result = [T]()

    for item in array {
      do {
        result.append(try T(item) )
      } catch {
        continue
      }
    }

    return result
  }
}

   - Parameter name: The name of the property that you want to map
   - Returns: A generic type if casting succeeds, otherwise it throws
   */
  func relationOrThrow<T : SafeMappable>(name: String) throws -> T {
    guard let key = name as? Key,
      value = self[key],
      dictionary = value as? JSONDictionary
