title: php type hint for type of "function" or "closure"
body: <p>What is the correct symbol to use if you want your type hint to denote a function?</p>
  
  <p>I'm using php 7.0</p>
  
  <pre><code>function FuncA (interger $A, array $B, ??Function?? $C){
             $C();
  }
  </code></pre>