Method agg

pandas/core/apply.py:279–300

Provide an implementation for the aggregators. Returns ------- Result of aggregation, or None if agg cannot be performed by this method.

(self)

        pass

    def agg(self) -> DataFrame | Series | None:
        """
        Provide an implementation for the aggregators.

        Returns
        -------
        Result of aggregation, or None if agg cannot be performed by
        this method.
        """
        func = self.func

        if isinstance(func, str):
            return self.apply_str()

        if is_dict_like(func):
            return self.agg_dict_like()
        elif is_list_like(func):
            # we require a list, but not a 'str'
            return self.agg_list_like()

        # caller can react
        return None

    def transform(self) -> DataFrame | Series:
        """