Implementing protocol in Swift respecting instancetype keyword

Question

I have protocol which simplifies objects initialization by standardizing initializer names. Here is how it looks like in Objective - C

@protocol CSModelInitialization <NSObject>

@required
+ (id)modelWithParameters:(NSDictionary *)parameters;

@optional
- (instancetype)initWithParameters:(NSDictionary *)parameters;

@end

Now I have created Swift class, let's call it TestClass which will implement this protocol. In Objective - C implementation would look something like this:

+ (instancetype)modelWithParameters:(NSDictionary *)parameters {

    SomeClass *object = [[self alloc] init];
    //Setting some properties from parameters NSDictionary...
    return object;
}

Now when I try to use similar approach in Swift I'm getting errors, like

Type 'TestClass' does not conform to protocol 'MyProtocol'

or `

'TestClass' is not convertible to 'Self'

Swift implementation looks like this:

import UIKit

public class TestClass: NSObject, MyProtocol {

    //MARK: MyProtocol

    public class func modelWithParameters(parameters: [NSObject : AnyObject]!) -> Self? {

        var object: TestClass = TestClass()
        //Setting some properties from parameters dictionary...
        return object
    }
}

I'm relatively new to Swift and linking to some example would be really awesome.