title: Change Python Key name in a list of non-identical dictionaries to another Key name
body: <p>In a list of non-identical dictionaries, two different Key names are randomly used to hold the same kind of value. For example "animal" and "beast" but all should just be "animal":</p>
  
  <pre><code>list = [{'beast': 'dog', 'age': 3, 'weather': 'cold'},
            {'animal': 'cat', 'age': 2, 'food': 'catnip'},
            {'animal': 'bird', 'age': 15, 'cage': 'no'}]
  </code></pre>
  
  <p>I need to replace key['beast'] with key['animal'].</p>
  
  <p>I have tried the following but only works if all the relevant Keys are "beast" which then can be renamed to "animal":</p>
  
  <pre><code>for pet in list:
      pet['animal'] = pet['beast'] 
      del pet['beast']
  </code></pre>
  
  <p>The same applies for another way:</p>
  
  <pre><code>for pet in list:
      pet['animal'] = pet.pop('beast')
  </code></pre>
  
  <p>I'd like the output to become:</p>
  
  <pre><code>[{'age': 3, 'weather': 'cold', '**animal**': 'dog'},
   {'age': 2, 'food': 'catnip', '**animal**': 'cat'},
   {'age': 15, 'cage': 'no', '**animal**': 'bird'}]
  </code></pre>