title: Which is faster? Checking if an element is already in a set, if not add it or just adding it anyway?
body: <p>Which way would be the fastest to add an element to a set? </p>
  
  <p>The way I see it you could do this in 2 different ways:</p>
  
  <ul>
  <li><p>Check if the element you want to add is allready in the set and if it is not in the set, add it.</p></li>
  <li><p>Just add it, because a set has unique elements. I am not sure this way will not throw an error.</p></li>
  </ul>