=> [(node, key, [key])] -- The graph; its ok for the
-- out-list to contain keys which arent
-- a vertex key, they are ignored
- -> [SCC (node, key, [key])]
+ -> [SCC (node, key, [key])] -- Topologically sorted
stronglyConnCompR [] = [] -- added to avoid creating empty array in graphFromEdges -- SOF
stronglyConnCompR edges