title: Use of unresolved identifier 'AccessToken' when using Facebook Swift SDK
body: <p>I work with Facebook Swift SDK and I'm trying to check if the user is logged in. I get error message <code>Use of unresolved identifier 'AccessToken'</code></p>
  
  <p>My code is:</p>
  
  <pre><code>       if let accessToken = AccessToken.current {
              // User is logged in, use 'accessToken' here.
  
          }
  </code></pre>