Search bar not working

Im making an app that uses the apple api to display information and when my search bar is clicked nothing happens. What do I do to fix it?

extension IntroTableVC: UISearchBarDelegate {

func searchClicked(_ searchBar: UISearchBar) {


Probably should look to StackOverFlow or the Apple Developers forums for answers. The question is about the Apple frameworks, not Swift. Could be asked about an Objective-C source.