title: Mongo DB query on multiple conditions
body: <p>I am trying to do a simple query based on two conditions in MongoDB using pymongo.</p>
  
  <p>I am using the sample restaurants data set from the tutorial documentation. I have:</p>
  
  <pre><code>from pymongo import MongoClient
  import pymongo
  import pandas as pd
  
  client = MongoClient()
  
  db = client.test
  
  cursor = db.restaurants.find({"$and":[{'borough':"Manhattan"},{"grades":{'grade':"A"}}]}
  
  for record in cursor:
      print record
  </code></pre>
  
  <p>I am just trying to print all the restaurants in Manhattan with a grade of 'B.' But this pulls back no results.  I have also tried</p>
  
  <pre><code>cursor = db.restaurants.find({"borough":"Manhattan", "grades.grade":"B"})
  </code></pre>
  
  <p>but this will only filter by the first condition and won't filter by the "grade."  It's exactly how it is laid out in the documentation but I can't get it to work.</p>