title: Pymongo case insensitive regex query over a list
body: <p>I have a list that I would like to query against using <code>$in</code> in pymongo, but I also need it to be case insensitive for each value in the list. Before I needed the list, my code looked something like this:</p>
  <pre><code>query = {'field': {'$regex': 'value', '$options': 'i'}}
  for i in col.find(query): print(i)
  </code></pre>
  <p>where col is the pymongo collection.</p>
  <p>I tried doing this:</p>
  <pre><code>query = {'field': {'$regex': {'$in':['value1', 'value2']}, '$options': 'i'}}
  for i in col.find(query): print(i)
  </code></pre>
  <p>but it doesn't seem to work</p>