protocol VCFinalDelegate {

func finishPassing()

}

class ViewController1: UIViewController, VCFinalDelegate{

//......
var param: NQTSearchParam!
var uid = String()

private func loadDoctorFromServer(param: NQTSearchParam?){
    progressHub.show(animated: true)
    let request = EVRequestDoctor.shared
    request.delegate = self
    request.findDoctorWithClinicID(clinicID: param?.clinicID, specialtyID: param?.specializationID)

    uid = (param?.clinicID)!
}



func finishPassing(){
    let id = uid
}

//......
}

class ViewController3: UIViewController{

//......

var delegate: VCFinalDelegate?

private func updateDoctorUI() {

    delegate?.finishPassing()
    print("id: (delegate?.finishPassing())") //nil

}

//......
}