Proper implementation of handleInputModeList in Custom Keyboard

A new API has been added in iOS 10 to present the list of other keyboards the user can switch to - the same list that appears when users long press the globe on a system keyboard. The declaration of the function is as follows:
func handleInputModeList(from view: UIView, with event: UIEvent)

My question is, what's the proper way to generate a UIEvent to supply? I was planning to call this function using a UILongPressGestureRecognizer but this API doesn't reveal UIEvents.