title: Using .sort with PyMongo
body: <p>With PyMongo, when I try to retrieve objects sorted by their 'number' and 'date' fields like this:</p>
  
  <pre><code>db.test.find({"number": {"$gt": 1}}).sort({"number": 1, "date": -1})
  </code></pre>
  
  <p>I get this error:</p>
  
  <pre><code>TypeError: if no direction is specified, key_or_list must be an instance of list
  </code></pre>
  
  <p>What's wrong with my sort query?</p>