title: merging Python dictionaries
body: <p>I am trying to merge the following python dictionaries as follow:</p>
  <pre><code>dict1= {'paul':100, 'john':80, 'ted':34, 'herve':10}
  dict2 = {'paul':'a', 'john':'b', 'ted':'c', 'peter':'d'}
  
  output = {'paul':[100,'a'],
            'john':[80, 'b'],
            'ted':[34,'c'],
            'peter':[None, 'd'],
            'herve':[10, None]}
  </code></pre>
  <p>I wish to keep all keys from both dictionaries.<br />
  Is there an efficient way to do this?</p>