title: pymongo - querying most recent N items
body: <p>What is the 'proper way' to retrieve most recent N items from the database?</p>
  
  <p>from tutorial and mongodb documentations it seems (besides using range queries)</p>
  
  <p><code>db.collection.find(skip = 0, limit=N, sort=[("_id", -1)])</code></p>
  
  <p>is it right?</p>