title: How to restrict multiple file selection in PickerView
body: <p>I'm using WKWebView to load one URL. And that URL will open a registration form, in that we have a provision to picking images and videos from device and upload.
  Here it is presenting picker view.</p>
  
  <p>But the problem is we are able to select multiple files at a time. But I want to restrict multiple file selection. How can I restrict of selecting multiple files. (I'm using Swift 3.0)</p>