title: Updating all values at a specific position in a dictionary
body: <p>I have a dictionary that looks like this</p>
  
  <pre><code>dict_ = {'ALPHA':(["data['ALPHA']", 'EMPTY'], 'N', 'N', 1),'BETA':(["data['BETA']", 'EMPTY'], 'N', 'N', 2),'GAMMA':(["data['GAMMA']", 'EMPTY'], 'N', 'N', 3)} 
  </code></pre>
  
  <p>I want to add a constant to the final integer of each value tuple, to get </p>
  
  <pre><code>dict_ = {'ALPHA':(["data['ALPHA']", 'EMPTY'], 'N', 'N', 6),'BETA':(["data['BETA']", 'EMPTY'], 'N', 'N', 7),'GAMMA':(["data['GAMMA']", 'EMPTY'], 'N', 'N', 8)} 
  </code></pre>
  
  <p>I tried</p>
  
  <pre><code>offset = 5
  dict_.update((x, y[3]+offset) for x, y in dict_.items())
  </code></pre>
  
  <p>which results in </p>
  
  <pre><code>{'ALPHA': 6, 'BETA': 7, 'GAMMA': 8}
  </code></pre>
  
  <p>is there a better way of preserving the rest of the structure and only update the desired position ?</p>