(self, agg_dict)
Returns an aggregation object from an aggregation group dict.

        Args:
            agg_dict (dict): a dictionary containing information
                about the stored aggregation group.

        Returns:
            A dict that contains metadata about the aggregation group
            as well as a chart object (instance of altair.Chart)
            with the combined chart object from the group.
Returns an aggregation object from an aggregation group dict.
Returns an aggregation object from an aggregation group dict .
def get_aggregation_group(self, agg_dict):
        """Returns an aggregation object from an aggregation group dict.

        Args:
            agg_dict (dict): a dictionary containing information
                about the stored aggregation group.

        Returns:
            A dict that contains metadata about the aggregation group
            as well as a chart object (instance of altair.Chart)
            with the combined chart object from the group.
        """
        raise NotImplementedError
def get_aggregation_group ( self , agg_dict ) : raise NotImplementedError