Example 'present from window' crashes on iPad

[Lily418]

Using an iPad Mini 2 running iOS 9.3.1 and building the example in XCode 7.3.

Running the example and then tapping 'Present from window' button causes the following crash:

Terminating app due to uncaught exception 'NSGenericException', reason: 'Your application has presented a UIAlertController (<UIAlertController: 0x12c561280>) of style UIAlertControllerStyleActionSheet. The modalPresentationStyle of a UIAlertController with this style is UIModalPresentationPopover. You must provide location information for this popover through the alert controller's popoverPresentationController. You must provide either a sourceView and sourceRect or a barButtonItem. If this information is not known when you present the alert controller, you may provide it in the UIPopoverPresentationControllerDelegate method -prepareForPopoverPresentation.'

Investigation lead me to this SO question suggesting extra properties are required for the popover on iPad, this makes sense because running the example on the iPhone 6s simulator worked fine.
UIActionSheet from Popover with iOS8 GM