title: Convert DataFrameGroupBy object to DataFrame pandas
body: <p>I had a dataframe and did a groupby in FIPS and summed the groups that worked fine.</p>
  
  <pre><code>kl = ks.groupby('FIPS')
  
  kl.aggregate(np.sum)
  </code></pre>
  
  <p>I just want a normal Dataframe back but I have a <code>pandas.core.groupby.DataFrameGroupBy</code> object. </p>