title: How to resolve the error dataframe not callable
body: <pre><code>Count = df.groupby("user_id", as_index=False).count()
  Mean = df.groupby("user_id", as_index=False).mean()
  
  dfMerged = pd.merge(df, count, how='right', on=['user_id'])
  dfMerged()
  </code></pre>