import numpy as np
import pandas as pd
result = data.groupby(groupbyvars).agg({'amount': [ pd.Series.sum, pd.Series.mean]}).reset_index()

data.groupby(groupbyvars).agg({'amount': [ pd.Series.sum(skipna=True), pd.Series.mean(skipna=True)]}).reset_index()

s_na_mean = partial(pd.Series.mean, skipna = True)
data.groupby(groupbyvars).agg({'amount': [ np.nansum, s_na_mean ]}).reset_index()

error: 'functools.partial' object has no attribute '__name__'

from numpy import nansum
from numpy import nanmean
data.groupby(groupbyvars).agg({'amount': [ nansum, nanmean]}).reset_index()

from functools import partial
s_na_mean = partial(pd.Series.mean, skipna = True)

import numpy as np
import pandas as pd

def nan_agg(x):
    res = {}

    res['nansum'] = x.loc[ not x['amount'].isnull(), :]['amount'].sum()
    res['nanmean'] = x.loc[ not x['amount'].isnull(), :]['amount'].mean()

    return pd.Series(res, index=['nansum', 'nanmean'])

result = data.groupby(groupbyvars).apply(nan_agg).reset_index()