         return HTTPStatusCode(HTTPResponse: self)
     }
     
-    @availability(iOS, introduced=7.0)
-    public convenience init?(URL url: NSURL, statusCode: HTTPStatusCode, HTTPVersion: String?, headerFields: [NSObject : AnyObject]?) {
+    @available(iOS, introduced=7.0)
+    public convenience init?(URL url: NSURL, statusCode: HTTPStatusCode, HTTPVersion: String?, headerFields: [String : String]?) {
         self.init(URL: url, statusCode: statusCode.rawValue, HTTPVersion: HTTPVersion, headerFields: headerFields)
     }
 }


// MARK: - Printing

extension HTTPStatusCode: DebugPrintable, Printable {
    public var description: String {
        return "\(rawValue) - \(localizedReasonPhrase)"
    }

        return inRange(500...599)
    }
    
    /// - returns: true if the status code is in the provided range, false otherwise.
    private func inRange(range: Range<Int>) -> Bool {
        return range.contains(rawValue)
    }
}

