title: same collectionview cell using multiple viewcontroller problem
body: <p>When I try to use the same cell in more than one viewcontroller, I get Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value error when I try to fill in the labels in the cell.</p>
  <pre class="lang-swift prettyprint-override"><code>func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -&gt; UICollectionViewCell {
          let cell = collectionView.dequeueReusableCell(withReuseIdentifier: &quot;cell&quot;, for: indexPath) as? CategoryCollectionViewCell
          
          cell?.categoryLabel.text = &quot;label&quot;
          
          cell!.contentView.layer.cornerRadius = 7.5
          return cell!
      }
  </code></pre>