title: How do you find duplicate strings in a list?
body: <p>I have a list with several stings, with some being duplicates. I need to pull out all the duplicate strings and append them into a new list. How can I do that?</p>
  
  <pre><code>list_i = ['a','b','a','c','a','c','g','w','s','c','d','a','b','c','a','e']
  </code></pre>