title: Python - Sum values in nested dict
body: <p>I have a nested dict as follows.</p>
  
  <pre><code>inv = {'jan':[10,20],'Feb':[33,40,50],'mar':[20,56],'apr':[20,21,30]}
      for value in inv.items():
  print(sum(inv.values()))
  </code></pre>
  
  <p>I want the sum of the values to be returned as total.</p>
  
  <p>The total should be 300 </p>