Method add

pandas/core/frame.py:9905–9910

(
        self, other, axis: Axis = "columns", level=None, fill_value=None
    )

    @Appender(ops.make_flex_doc("add", "dataframe"))
    def add(
        self, other, axis: Axis = "columns", level=None, fill_value=None
    ) -> DataFrame:
        return self._flex_arith_method(
            other, operator.add, level=level, fill_value=fill_value, axis=axis
        )

    @Appender(ops.make_flex_doc("radd", "dataframe"))
    def radd(