title: How to change ElementTree attribute keys?
body: <p>I want to change the attributes of an existing element, and not just the values, but add/remove/change the keys too.  For example,  </p>
  
  <pre><code>&lt;frame_geometry name="border" has_title="false"/&gt;  
  </code></pre>
  
  <p>I would like to add: rounded_top_left="5" etc...<br>
  Is modifying element attributes' keys after creation possible?</p>
  
  <p>If not, perhaps I could use a workaround, something like storing all the element's attributes in a temporary dictionary and then creating a new element from that +/- any desired changes?<br>
  This solution is not desirable however because the elements I need to modify have several subelements also...</p>