title: Mongo: $push is not working with array
body: <p>I have a piece of python code using pymongo. It checks in the collection if there's already a document present with 'sn'=sn. If yes, then update ("$push" date and sn_ch values to "owner" array, else create a new document. When I run this, I don't see any error, but the array doesn't get updated..</p>
  
  <pre><code>    Module = {'sn':sn,'descr':descr,'owners':[{'date':date,'sn_ch':sn_ch}],'name':name}
      myCur = db.modules.find({'sn':sn}).count()
      print(myCur)
      if myCur &gt;                 
              db.mobules.update({'sn':sn}, {'$push': {'owners':{'date':date,'sn_ch':sn_ch}}})
      else:
              db.modules.insert(Module)
  </code></pre>
  
  <p>Thanks in advance!</p>