title: find Key for value in python when key associated with multiple values
body: <p>For a dictionary of the type</p>
  
  <pre><code>{'key1': ['v1','v2','v3', ...],
   'key2': ['v2','v4', ...],
    ... }
  </code></pre>
  
  <p>How do I</p>
  
  <ol>
  <li>Find any key associated with a value v</li>
  <li>Print that k:[value set] pair to a new dictionary</li>
  </ol>