title: Xcode 7 Null passed to a callee that requires a non-null argument
body: <p>i updated xcode 7 and gives this error</p>
  
  <p>Null passed to a callee that requires a non-null argument</p>
  
  <pre><code> _recorder = [[AVAudioRecorder alloc]initWithURL:[NSURL fileURLWithPath:[NSString stringWithFormat:@"%@/%@.%@", [NSHomeDirectory() stringByAppendingString:@"/Documents"], name, extension]] settings:nil error:nil];
  </code></pre>