pandas.Series.add

Series.add(other, level=None, fill_value=None)

Binary operator add with support to substitute a fill_value for missing data in one of the inputs

other: Series or scalar value fill_value : None or float value, default None (NaN)

Fill missing (NaN) values with this value. If both Series are missing, the result will be missing

level : int or name

Broadcast across a level, matching Index values on the passed MultiIndex level

result : Series