let rec dfs toIn toOut toCheckEntry acc start gr =
        let dfs' = dfs toIn toOut toCheckEntry
        let innerDfs newAcc v w =
            if toCheckEntry start v w newAcc
            then dfs' newAcc v gr
            else newAcc
        let pastInAcc = toIn start acc
        let pastChildrenAcc = Map.fold innerDfs pastInAcc <| getAdjList start gr
        let pastOutAcc = toOut start pastChildrenAcc
        pastOutAcc