title: Find minimum non zero value in dictionary (Python)
body: <p>I have a dictionary and I would like to get the key whose value is the minimum nonzero.</p>
  
  <p>E.g. given the input:</p>
  
  <pre><code>{1:0, 2:1, 3:2}
  </code></pre>
  
  <p>It would return 2.</p>