title: finding top k largest keys in a dictionary python
body: <p>Lets say I have a dictionary:</p>
  
  <pre><code>{key1:value1........... keyn:valuen}
  </code></pre>
  
  <p>So lets say I want to write a function</p>
  
  <pre><code>def return_top_k(dictionary, k):
  
      return list_of_keys_sorted   
  </code></pre>
  
  <p>What is the most efficient way (in terms of big O) to get the keys which have the top k values (maintaining the order i.e the highest value key is present in the beginning.. and so on.)</p>