title: python add value in dictionary in lambda expression
body: <p>Is it possible to add values in dictionary in lambda expression?</p>
  
  <p>That is to implement a lambda which has the similar function as below methods.</p>
  
  <pre><code>def add_value(dict_x):
      dict_x['a+b'] = dict_x['a'] + dict_x['b']
      return dict_x
  </code></pre>