title: Can not invoke error in postrequest in swift
body: <p>code:</p>
  
  <pre><code>var request = NSMutableURLRequest(URL: NSURL(string:"http://../projects/quotes/index.php/synchronization/get_daily_quotes")!)
          var session = NSURLSession.sharedSession()
          request.HTTPMethod = "POST"
          var err: NSError?
  
          var params = ["user_id":"1","number_of_quotes":"2","category_ids":"1"]as NSDictionary
  
          request.HTTPBody = NSJSONSerialization.dataWithJSONObject(params, options: nil, error: &amp;err) // This Line fills the web service with required parameters.
          request.addValue("application/json", forHTTPHeaderField: "Content-Type")
          request.addValue("application/json", forHTTPHeaderField: "Accept")
  
          var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -&gt; Void in
              var strData = NSString(data: data, encoding: NSUTF8StringEncoding)
              var err1: NSError?
               var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(strData, options: NSJSONReadingOptions.MutableContainers, error: nil) as! NSDictionary
  
              println("json2 :\(jsonResult)")
  
              if((err != nil)) {
                  println(err!.localizedDescription)
              }
              else {
                  var success = jsonResult["success"] as? Int
                  println("Succes: \(success)")
              }
          })
  
          task.resume()
      }
  </code></pre>
  
  <p>I am trying send postrequest with json arguments.it gives me error as "Cannot invoke 'JSONObjectWithData' with an argument list of type '(NSString?, options: NSJSONReadingOptions, error: nil)".Why i am getting this error?any help will be appreciated.</p>