pandas.Series.sum

Series.sum(axis=0, dtype=None, out=None, skipna=True, level=None)

Return sum of values NA/null values are excluded

skipna : boolean, default True
Exclude NA/null values
level : int, default None
If the axis is a MultiIndex (hierarchical), count along a particular level, collapsing into a smaller Series

Extra parameters are to preserve ndarrayinterface.

sum : float (or Series if level specified)