all the grouping instances to handle in this grouper for example for grouper list to groupby, need to pass the list
whether this grouper will give sorted result or not
the indexer created by Grouper some groupers (TimeGrouper) will sort its axis and its group_info is also sorted, so need the indexer to reorder
This is an internal Grouper class, which actually holds the generated groups
Hover to see nodes names; edges to Self not shown, Caped at 50 nodes.
Using a canvas is more power efficient and can get hundred of nodes ; but does not allow hyperlinks; , arrows or text (beyond on hover)
SVG is more flexible but power hungry; and does not scale well to 50 + nodes.
All aboves nodes referred to, (or are referred from) current nodes; Edges from Self to other have been omitted (or all nodes would be connected to the central node "self" which is not useful). Nodes are colored by the library they belong to, and scaled with the number of references pointing them
