问如何使用闭包在两个ViewController之间传递数据

EN

 @IBAction func push(sender: UIButton) {
        let v2Obj = storyboard?.instantiateViewControllerWithIdentifier("v2ViewController") as! v2ViewController
        
        v2Obj.completionBlock = {[weak self] dataReturned in
            //Data is returned **Do anything with it **
            print(dataReturned)
        }
        navigationController?.pushViewController(v2Obj, animated: true)
        
    }

import UIKit
typealias v2CB = (infoToReturn :String) ->()
class v2ViewController: UIViewController {
        var completionBlock:v2CB?
    override func viewDidLoad() {
        super.viewDidLoad()
    }

    func returnFirstValue(sender: UIButton) {
        guard let cb = completionBlock else {return}
        cb(infoToReturn: "any value")
    }
    
}

typealias CompletionHandler = (_ response: NSDictionary?, _ statusCode: Int?, _ error: NSError?) -> Void

    func doRequestFor(_ url : String, method: HTTPMethod, dicsParams : [String: Any]?, dicsHeaders : [String: String]?, completionHandler:@escaping CompletionHandler) {

        if !NetworkReachablity().isNetwork() {
            return
        }

        if (dicsParams != nil) {print(">>>>>>>>>>>>>Request info url: \(url) --: \(dicsParams!)")}
        else {print(">>>>>>>>>>>>>Request info url: \(url)")}

        Alamofire.request(url, method: method, parameters: dicsParams, encoding:
            URLEncoding.default, headers: dicsHeaders)

        .responseJSON { response in
            self.handleResponse(response: response, completionHandler: completionHandler)
        }
    }

        ServiceWrapper().doRequestFor(url, method: .post, dicsParams: param, dicsHeaders: nil) { (dictResponse, statusCode, error) in

        }