>>> print(pd.DatetimeIndex.fillna.__doc__) Fill NA/NaN values with the specified value Parameters ---------- value : scalar Scalar value to use to fill holes (e.g. 0). This value cannot be a list-likes. downcast : dict, default is None a dict of item->dtype of what to downcast if possible, or the string 'infer' which will try to downcast to an appropriate equal type (e.g. float64 to int64 if possible) Returns ------- filled : %(klass)s