For sum, prod, count, etc. there is a parameter level which is internally rewritten into groupby.

I propose that the level parameter for these aggregations be deprecated and instead recommend to users that they use the groupby syntax.

The functions that would be affected are:

• any
• all
• count
• sum
• prod
• max
• min
• mean
• median
• skew
• kurt
• sem
• var
• std
• mad

I believe this list is comprehensive.