margin : float
            Minimum space between Sankey outlines and the edge of the plot
            area.
        tolerance : float
            Acceptable maximum of the magnitude of the sum of flows.  The
            magnitude of the sum of connected flows cannot be greater than
            *tolerance*.
        **kwargs
            Any additional keyword arguments will be passed to :meth:`add`,
            which will create the first subdiagram.

        See Also
        --------
        Sankey.add
        Sankey.finish

        Examples
        --------
        .. plot:: gallery/specialty_plots/sankey_basics.py
        r