Пример
import pandas as pd
import numpy as np
t=pd.DataFrame({'c1': {(1, 1, 1): 1, (1, 2, 9): 2, (2, 1, 3): np.nan, (2, 1, 7): 4, (4, 2, 2): 6}, 'c2': {(1, 1, 1): 3, (1, 2, 9): 3, (2, 1, 3): 3, (2, 1, 7): 1, (4, 2, 2): 2}})
print(t .groupby(level=...