SwiftHTTP request.GET中如何return true or false

var request = HTTPTask()
request.GET("http://vluxe.io", parameters: nil, success: {(response: HTTPResponse) in
    if response.responseObject != nil {
        let data = response.responseObject as NSData
        let str = NSString(data: data, encoding: NSUTF8StringEncoding)
        println("response: \(str)") //prints the HTML of the page
        // 比如这里我想写个if 然后返回true or false
       // 但会得到错误 Type 'Void' does not conform to protocol 'BooleanLiteralConvertible'
    }
},failure: {(error: NSError, response: HTTPResponse?) in
    println("error: \(error)")
})