title: find different elements of two lists
body: <p>I have two lists, l1 and l2 and I want to compare the lists l1 and l2. Then I want to 
   find list elements that are different from each other. Lists are as follows:</p>
  
  <pre><code>l1= [('A', '2', '3', '4', '5', '6'), ('F', '2', '4', '2.2', '2.7', '3'), ('G', '5', '2.1', '3.4', '1.5', '2'),('H', 'L', 'L', 'D', 'C', 'B')]
  
  l2= [('A', '2', '3', '4', '5', '6'),('H', 'L', 'L', 'D', 'C', 'B')]
  </code></pre>
  
  <p>the output I want is:</p>
  
  <pre><code>l3=[('F', '2', '4', '2.2', '2.7', '3'), ('G', '5', '2.1', '3.4', '1.5', '2')]
  </code></pre>
  
  <p>How can I do that?</p>