title: How to create custom album in Swift 3 iOS 10
body: <p>This may sound repetitive but after searching for while I still not got the intended answer for Swift 3.
  After creating a placeholder for asset when i'm trying to add Assets using <code>addAssets()</code> method Xcode suggesting me to Cast assetPlacehoder to FastEnumeration type. And when I did so it is causing an exception. Can anybody help me out?</p>