title: How to make a class conform to a protocol in Swift?
body: <p>in Objective-C:</p>
  
  <pre><code>@interface CustomDataSource : NSObject &lt;UITableViewDataSource&gt;
  
  @end
  </code></pre>
  
  <p>in Swift:</p>
  
  <pre><code>class CustomDataSource : UITableViewDataSource {
  
  }
  </code></pre>
  
  <p>However, an error message will appear:</p>
  
  <ol>
  <li>Type 'CellDatasDataSource' does not conform to protocol 'NSObjectProtocol'</li>
  <li>Type 'CellDatasDataSource' does not conform to protocol 'UITableViewDataSource'</li>
  </ol>
  
  <p>What should be the correct way ?</p>