title: Unowned self in a closure in a closure
body: <p>If I have a closure in another closure is it enough to use unowned/weak once in the outer closure to avoid retain cycles?</p>
  
  <p>Example:</p>
  
  <pre><code>foo.aClosure({[unowned self] (allowed: Bool) in
              if allowed {
                  self.doStuff()
  
                  self.something.anotherClosure({ (s:String) -&gt; (Void) in
                      self.doSomethingElse(s)
                  })   
              }
          })
  </code></pre>