title: Common elements comparison between 2 lists
body: <pre><code>def common_elements(list1, list2):
      """
      Return a list containing the elements which are in both list1 and list2
  
      &gt;&gt;&gt; common_elements([1,2,3,4,5,6], [3,5,7,9])
      [3, 5]
      &gt;&gt;&gt; common_elements(['this','this','n','that'],['this','not','that','that'])
      ['this', 'that']
      """
      for element in list1:
          if element in list2:
              return list(element)
  </code></pre>
  
  <p>Got that so far, but can't seem to get it to work! </p>
  
  <p>Any ideas?</p>