title: Result of call is unused
body: <p>Right below the second comment, I receive an error of "Result of call to 'taskForDeleteMethod' is unused. Why is this when I use the results and error in the closure following the call?</p>
  
  <pre><code>func deleteSession(_ completionHandlerForDeleteSession: @escaping (_ success: Bool, _ error: NSError?) -&gt; Void) {
  
      /* 1. Specify parameters, method (if has {key}), and HTTP body (if POST) */
      // There are none...
  
      /* 2. Make the request */
      taskForDELETEMethod { (results, error) in
  
          /* 3. Send the desired value(s) to completion handler */
          if let error = error {
              print("Post error: \(error)")
              completionHandlerForDeleteSession(false, error)
          } else {
              guard let session = results![JSONKeys.session] as? [String: AnyObject] else {
                  print("No key '\(JSONKeys.session)' in \(results)")
                  return
              }
  
              if let id = session[JSONKeys.id] as? String {
                  print("logout id: \(id)")
                  completionHandlerForDeleteSession(true, nil)
              }
          }
      }
  }
  </code></pre>