Crash when background color set to "black" using delegate

[hemangshah]

If you pass "black" background color using a delegate it will crash. However it will not crash if I create black color like this (UIColor.init(red: 0.0, green: 0.0, blue: 0.0, alpha: 1.0)).

func swiftyOnboardBackgroundColorFor(_ swiftyOnboard: SwiftyOnboard, atIndex index: Int) -> UIColor? {
   return UIColor.black //This will crash. 🔥
}

[spaquet]

Based on the code it looks like the lib expects RGB defined color.