running error Unexpectedly found nil while unwrapping an Optional value

[tuotuoZ]

I am testing out the HUD.flash(.success, delay: 1.0) in a new class.
And I got this running error:
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value

from line 122
let view: UIView = view ?? viewToPresentOn ?? UIApplication.shared.keyWindow!

[Kamil-H]

@tuotuoZ
I don't know your exact case, but in mine using a onView parameter function where you can provide UIView on which you want to show dialog helped me. In your case it would be:
HUD.flash(.success, onView: **view**, delay: 1.0, completion: nil)
where view is a root view of my ViewController.