dxfhjbyilo3716 dxfhjbyilo3716 25-12-2023 Computers and Technology contestada a) How to create a multi-index data frame in Python? b) How to add a new column that contains an operation between existing columns in Python? c) What type is pop_df['f_u18'] in Python? d) What type is pop_df['f_u18'].unstack() in Python?