How to translate setCompletionHandler:^ from Obj-c to Swift?

Question

iOS

Hello everyone .
There is a code written on the object
[shareDialog setCompletionHandler:^(VKShareDialogControllerResult result) {
[self dismissViewControllerAnimated:YES completion:nil];
while shareDialog is
let shareDialog = VKShareDialogController()
and I can call shareDialog.setCompletionHandler
but what to do next to reproduce the code on the object, I don’t understand point-blank
Maybe someone came across? This is sdk vk