title: python compare difference between two lists
body: <p>I have two lists like this:</p>
  
  <pre><code>newList = (
      (1546, 'John'),
      (8794, 'Michael'),
      (892416, 'Dave'),
      (456789, 'Lucy'),
      )
  
  oldList = (
      (1546, 'John'),
      (8794, 'Michael'),
      (892416, 'Dave'),
      (246456, 'Alexander')
      )
  </code></pre>
  
  <p>I would like to have a function comparing both lists. It would be something like this:</p>
  
  <pre><code>def compare(new, old):
      print('Alexander is not anymore in the new list !')
      print('Lucy is new !')
      return newList 
  </code></pre>
  
  <p>I would like to compare with id of every person which is unique.</p>
  
  <p>Edit: The result would be my function compare. It prints the difference.
  I don't know how to start</p>