Swift3.0中出现的问题：
Cannot convert value of type '(URLSessionDataTask?,NSError) -> ()' to expected argument type '((URLSessionDataTask?,Error) -> Void)?'
解决方法：
将NSError转换成Error,参考链接：[参考链接](http://http://stackoverflow.com/questions/39640029/afnetwoking-with-swift -3-0-xcode-8-post-request-get-request)原文链接：https://www.f2er.com/swift/321869.html
