title: Get number of results from aggregate in mongo (using python)
body: <p>I'm using aggregate in order to get some documents ( I can't use find that way). I used to use the <code>.count()</code> function to know how many documents I got.
  This function isn't working with aggregate. When I tried <code>$count</code> I just got the count without all the documents.
  What else can I do?</p>