title: mongodb query $in on a Hash field
body: <p>I'm trying to make a query to find values existing in an Hash fields
  my document<img src="https://i.stack.imgur.com/apB48.png" alt="enter image description here"></p>
  
  <p>I would like to retrieve the Documents that have n11 and n13 in durations field.</p>
  
  <p>I though it will be like that.</p>
  
  <pre><code>{
  "durations" : { $in: ['n11','n12']}
  }
  </code></pre>
  
  <p>but it doesn't work</p>
  
  <pre><code>{
  "durations" : { $in: [1,2,3,4,5,6,7,8,9]}
  }
  </code></pre>
  
  <p>but in both case, I have no results executing the query.</p>
  
  <p>Thanks in advance for your help
  I also tried with keys</p>