title: How to fix error – "No Visible @interface for ARCamera"?
body: <p>I'm trying to build a project that I <a href="https://github.com/StephenGuanqi/Unity-ARKit-Plugin" rel="nofollow noreferrer">downloaded from git</a> and I got some errors in the Xcode beta 9. 
  I noticed that there are some things that are deprecated like <code>ARWorldTrackingSessionConfiguration</code> so I changed them and they were fixed. But I get an error that I can't fix, this is the part from the code:</p>
  
  <pre><code>matrix_float4x4 projectionMatrix = [frame.camera projectionMatrixWithViewportSize: nativeSize
                                      orientation:[[UIApplication sharedApplication] statusBarOrientation]
                                      zNear:(CGFloat)unityCameraNearZ 
                                      zFar:(CGFloat)unityCameraFarZ];
  </code></pre>
  
  <p>I could not fix this and I don't know what to do.
  the error for that is this: </p>
  
  <blockquote>
    <p>No visible @interface for 'ARCamera' declares the selector 'projectionMatrixWithViewportSize:orientation:zNear:zFar</p>
  </blockquote>
  
  <p>Hope you can help me with this issue?</p>
  
  <p>Thank you.</p>