title: Cannot register array of UICollectionViewCells
body: <p>I'm trying to register an array of UICollectionViewCells, but in the loop I get this error: <strong><em>cannot invoke 'register' with an argument lsit of type '(UICollectionViewCell, forCellWithResueidentifier: String)'</em></strong></p>
  
  <pre><code>My playground
  ***let cell1 = UICollectionViewCell()
  let cell2 = UICollectionViewCell()
  let cells = [cell1, cell2]
  let collection = UICollectionView(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout())
  for cell in cells {
      collection.register(cell, forCellWithReuseIdentifier: "hello")
  }***
  
  Any ideas?
  Thanks in advance
  </code></pre>