func myInstanceMethod()
{
    let myClosure =
    {
       [weak self] (result : Bool) in
       if let this = self
       { 
           this.anotherInstanceMethod()
       }
    }   

    functionExpectingClosure(myClosure)
}

如果我使用嵌套函数代替闭包(或者甚至是必要的检查),或者使用这样的嵌套函数甚至是很好的做法,那么我如何执行自检的空检查,即

func myInstanceMethod()
{
    func nestedFunction(result : Bool)
    {
        anotherInstanceMethod()
    }

    functionExpectingClosure(nestedFunction)
}