Update README.md

README.md

@@ -96,16 +96,19 @@ SwiftOverlays.removeAllBlockingOverlays()
 
 ```
 
-### Using with UITableViewController
+### Using with UITableViewController/UICollectionViewController
 
 You can't use SwiftOverlays convenience methods directly with UITableViewController - because its view is, well, an UITableView, and overlay will be scrolled along with it.
 
 Instead I suggest using UIViewController instead of UITableViewController and adding UITableView as a subview.
+(the same applies to UICollectionViewController)
 
 If for some reason you can't use UIViewController, you can do something like:
 ```swift
-SwiftOverlays.showCenteredWaitOverlayWithText(self.view.superview!, text: "Please wait...")
-SwiftOverlays.removeAllOverlaysFromView(self.view.superview!)
+if let superview = self.view.superview {
+  SwiftOverlays.showCenteredWaitOverlayWithText(superview, text: "Please wait...")
+  SwiftOverlays.removeAllOverlaysFromView(superview)
+}
 ```
 
 (but in that case overlay will be added to the superview, and you should obviously do that only if superview is available - for example in viewDidAppear method of your controller.).