title: Python add key to list of dictionary if key doesn't exist
body: <p>I want to add the key 'Name' to list of dictionaries in whichever dictionary 'Name' doesn't exist.</p>
  <p>For example,</p>
  <pre><code>[dict(item, **{'Name': 'apple'}) for item in d_list] 
  </code></pre>
  <p>will update value of key 'Name' even if key already exists and</p>
  <pre><code>[dict(item, **{'Name': 'apple'}) for item in d_list if 'Name' not in item]
  </code></pre>
  <p>returns empty list</p>