title: Repeat string in one element in a set using Python3
body: <p>I was making the difference between two sets to see what had changed when I noticed that whenever I had one element which was a repeated sequence it would be represented as only one char. </p>
  
  <p>Example:</p>
  
  <pre><code>&gt;&gt;&gt; set("aaaa") 
  {'a'}
  </code></pre>
  
  <p>How can I represent it as {'aaaa'} so I can make the diff between two sets and get the right value? If it's not possible using sets, what is the easiest way to compare two data structures and get the diff in python3?</p>
  
  <p>Example:</p>
  
  <pre><code> &gt;&gt;&gt; a = set(['red', 'blue', 'green'])
   &gt;&gt;&gt; b = set(['red', 'green'])
   &gt;&gt;&gt; a
   {'green', 'red', 'blue'}
   &gt;&gt;&gt; b
   {'red', 'green'}
   &gt;&gt;&gt; a - b
   {'blue'}
  </code></pre>