title: Sort keys in dictionary by value in a list in Python
body: <p>I have seen <a href="https://stackoverflow.com/questions/613183/python-sort-a-dictionary-by-value">this post</a> and <a href="https://stackoverflow.com/questions/72899/in-python-how-do-i-sort-a-list-of-dictionaries-by-values-of-the-dictionary">this post</a> as well as many others, but haven't quite found the answer to my question nor can I figure it out.  </p>
  
  <p>I have a dictionary of lists.  For example it looks like:</p>
  
  <pre><code>Dict = {'a':[1,2,3,4], 'b':[9,8,7,6], 'c':[8,5,3,2]}
  </code></pre>
  
  <p>I want to return a list of the keys sorted (descending/reverse) based on a specific item in the lists.  For example, I want to sort a,b,c based on the 4th item in each list.</p>
  
  <p>This should return the list <code>sorted_keys = ['b','a','c']</code> which were sorted by values <code>[6,4,2]</code>.  </p>
  
  <p>Make sense?  Please help...thanks!</p>