import UIKit

protocol StoryboardInitiable {
    static func loadFromMainStoryboard() -> Self?
    static func loadFromMainStoryboardForced() -> Self
}

extension StoryboardInitiable where Self : UIViewController {
    static func loadFromMainStoryboard() -> Self? {
        return UIStoryboard(name: "Main", bundle: Bundle.main).instantiateViewController(withIdentifier: String(describing: self)) as? Self
    }

    static func loadFromMainStoryboardForced() -> Self {
        guard let vc = loadFromMainStoryboard() else { fatalError("Could not load \(String(describing:self)) from storyboard.") }

        return vc
    }
}

class AnotherViewController : UIViewController, StoryboardInitiable { }

let newVC = AnotherViewController.loadFromMainStoryboard()              // AnotherViewController?
let newVCForced = AnotherViewController.loadFromMainStoryboardForced()  // AnotherViewController