title: Trying to add pull to refresh in Swift 4 but getting an error
body: <p>I need help fixing this issue! I am adding pull to refresh to my table view. When I pull to refresh I want the articles to refresh. If someone who knows this would help me would be great, and if there is anything else wrong too.</p>
  
  <pre><code>Argument of '#selector' does not refer to an '@objc' method, property, or initializer
  </code></pre>
  
  <p>The error is here:</p>
  
  <pre><code>refreshControl.addTarget(self, action: #selector(fetchArticles(fromSource: source)), for: .valueChanged)
      return refreshControl
  }()
  </code></pre>
  
  <p>Here is the function <code>fetchArticles</code>:</p>
  
  <pre><code>@objc func fetchArticles(fromSource provider: String){
      ...
  }
  </code></pre>