title: Python, Combining lists within a dict
body: <p>Is it possible to combine lists in a dict to a new key?
  For example, i have a dict setup</p>
  
  <pre><code>    ListDict = {
      'loopone': ['oneone', 'onetwo', 'onethree'],
      'looptwo': ['twoone', 'twotwo', 'twothree'],
      'loopthree': ['threeone', 'threetwo', 'threethree']}
  </code></pre>
  
  <p>I want a new key called 'loopfour' which contains the lists from 'loopone', 'looptwo', and 'loopthree'</p>
  
  <p>So its list would look like</p>
  
  <pre><code>    ['oneone', 'onetwo', 'onethree', 'twoone', 'twotwo', 'twothree', 'threeone', 'threetwo', 'threethree']
  </code></pre>
  
  <p>and can be called using ListDict['four'] and return the combined list</p>