Swift initialize Self in a static methods -

having problem getting work, inside user.provideinstance i'm unable initialize self , return. thoughts?

extension nsmanagedobject {     public convenience init(managedobjectcontext: nsmanagedobjectcontext) {         let entity = nsentitydescription.entityforname(string(self.dynamictype), inmanagedobjectcontext: managedobjectcontext)!         self.init(entity: entity, insertintomanagedobjectcontext: managedobjectcontext)     } }  public protocol deserializable {     static func provideinstance(json: [nsobject: anyobject]) -> self }  @objc(user) public class user: nsmanagedobject, deserializable {      public static func provideinstance(json: [nsobject: anyobject]) -> self {        let context = dicontainer.instance.resolve(coredatastack.self).managedobjectcontext        let instance = self.init(managedobjectcontext: context)        return instance     } } 

error on let instance = self.init(managedobjectcontext: context):

constructing object of class type self metatype value must use required initializer

why bother initializers?

extension nsmanagedobject {     class func provide(managedobjectcontext managedobjectcontext: nsmanagedobjectcontext) -> self {         let entity = nsentitydescription.entityforname(string(self.dynamictype), inmanagedobjectcontext: managedobjectcontext)!         return self.init(entity: entity, insertintomanagedobjectcontext: managedobjectcontext)     } }  public protocol deserializable {     static func provideinstance(json: [nsobject: anyobject]) -> self }  @objc(user) public class user: nsmanagedobject, deserializable {      public static func provideinstance(json: [nsobject: anyobject]) -> self {         let context = ...         let instance = self.provide(managedobjectcontext: context)         return instance     } } 

the problem initializers not inherited, unless required. , cannot create required initializer in extension.