title: apply() not working as expected
body: <p>I'm new to javascript, and came across the 'apply' method. 
  As an exercise, I've tried to create a wrapper function for all functions, like the following snippet. 1. Why is this not working as expected, and 2. how can I create a wrapper function for all functions?</p>
  
  <pre><code>function funcWrapper(func){
     return func.apply(this, arguments);
  };
  
  function sum(num1, num2){
     return num1 + num2;
  }
  
  funcWrapper(sum, 2, 3); 
  // expected 5, but returns
  // function sum(num1, num2){
  //    return num1 + num2;
  // }2
  </code></pre>