improve performance fetching data from mongodb
<pre><code>earnings = self.collection.find({}) #return 60k documents
----
data_dic = {'score': [], "reading_time": [] }
for earning in earnings:
    data_dic['reading_time'].append(earning["reading_time"])
    data_dic['score'].append(earning["score"])
----
df = pd.DataFrame()
df['reading_time'] = data_dic["reading_time"]
df['score'] = data_dic["score"]
</code></pre>

<p>The code between --- takes 4 seconds to complete. How can I improve this function ?</p>