title: UIScreen.main.bounds.width returning nil in Swift 3
body: <p>In my project, I got messed up with two versions of app. I propably copied the project file and it created a problem. This line</p>
  
  <pre><code>myLogo.frame.size.width = UIScreen.main.bounds.width
  </code></pre>
  
  <p>shows, that <code>UIScreen.main.bounds.width</code> returns nil. How is that even possible? </p>
  
  <blockquote>
    <p>fatal error: unexpectedly found nil while unwrapping an Optional value</p>
  </blockquote>
  
  <p>What could be the reason and how can I repair it?</p>
  
  <p>I'm working on the latest Xcode and writing in Swift 3.</p>