title: How can I iterate over and modify the values in a dict?
body: <pre><code>records = {'foo':foo, 'bar':bar, 'baz':baz}
  </code></pre>
  
  <p>I want to change the values to <code>0</code> if it is <code>None</code>. How can I do this?</p>
  
  <p>eg:</p>
  
  <pre><code>records = {'foo':None, 'bar':None, 'baz':1}
  </code></pre>
  
  <p>I want to change <code>foo</code> and <code>bar</code> to <code>0</code>.
  Final dict: </p>
  
  <pre><code>records = {'foo':0, 'bar':0, 'baz':1}
  </code></pre>