To group by in group by and average with Python Pandas, we can use the mean method.
For instance, we write
df.groupby(['org']).mean().groupby(['cluster']).mean()
to call groupby to group values by the org column value.
And then we call mean to get the mean of the grouped values.
Then we call groupby again to group the returned values by the cluster column.
And finally we call mean again to get the mean of those grouped values.
