vel0segs = [polygon0, polygon1, ...]
            polygon0 = [[x0, y0], [x1, y1], ...]

    allkinds : ``None`` or [level0kinds, level1kinds, ...]
        Optional list of all the polygon vertex kinds (code types), as
        described and used in Path. This is used to allow multiply-
        connected paths such as holes within filled polygons.
        If not ``None``, ``len(allkinds) == len(allsegs)``. The lists
        should look like ::

            level0kinds = [polygon0kinds, ...]
            polygon0kinds = [vertexcode0, vertexcode1, ...]

        If *allkinds* is not ``None``, usually all polygons for a
        particular contour level are grouped together so that
        ``level0segs = [polygon0]`` and ``level0kinds = [polygon0kinds]``.

    **kwargs
        Keyword arguments are as described in the docstring of
        `~.Axes.contour`.

    %(contour_set_attributes)s
    NFr