title: addit function with variables
body: <p>I want to know what the following code means and what each of <code>a</code>, <code>b</code>, and <code>c</code> become:</p>
  
  <pre><code>def addit(a,b,*c):
       return a+b+sum(c)
  
      addit(3,5,15,21,5)
  </code></pre>