title: Handle multiple errors with one UIAlertController
body: <p>I have two classes which provide delegate methods that report various errors when fetching data from an API. The <code>HttpAPI</code> fetches weather data and the <code>RadarAPI</code> fetches a radar image. The code below is in the <code>HomeViewController</code> which handles the data or errors from each API.</p>
  
  <pre><code>// MARK: - HttpAPI Delegate
  
  extension HomeViewController: HttpAPIDelegate {
  
      func apiSessionError(_ error: Error) {
          // show alert with error from url session
      }
  
      func apiHttpError(_ code: Int) {
          // show alert with HTTP error code
      }
  
      func apiJsonError(_ error: Error) {
          // show alert with json error
      }
  
      func apiSuccess(_ json: [String: Any]) {
          // update app with weather data
      }
  }
  
  // MARK: - RadarAPI Delegate
  
  extension HomeViewController: RadarAPIDelegate {
  
      func radarSessionError(_ error: Error) {
          // show alert for url session error
      }
  
      func radarHttpError(_ code: Int) {
          // show alert with HTTP response error code
      }
  
      func radarImageError(_ error: String) {
          // show alert with image parsing error message
      }
  
      func radarSuccess(_ image: UIImage) {
          // update app with weather radar image
      }    
  }
  </code></pre>
  
  <p>I would like to show an alert if an error occurs from fetching the weather data or when retrieving the radar image. The problem is that if an error occurs in the <code>HttpAPI</code> then the <code>RadarAPI</code> will also give an error; therefore, two <code>UIAlertControllers</code> will be presented which is not recommended.</p>
  
  <p>How can I handle multiple error messages and present those errors in a single <code>UIAlertController</code>? </p>