swift方法参数遵守多继承和遵守多个协议

参数继承协议

OC中

id<delegate>

Swift 3

protocol<A, B>

Swift 4

A & B

    open func contactPicker(from viewController: UIViewController & WYContactDelegate, completion: (() -> Void)? = nil) {
        delegate = viewController
        handle.contactPicker(from: viewController, completion: completion)
    }

多协议

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