`exception NoColoring`

### Graph coloring for graphs with integer marks

`module type GM = sig ... end`

Minimal graph signature for `Mark`. Sub-signature of `Sig.IM`.

`module Mark (G : GM) : sig ... end`

Provide a function for `k`-coloring a graph with integer marks. The provided function is more efficient that the one provided by functor `Make` above.

### Graph coloring for graphs without marks

`module type G = sig ... end`

Minimal graph signature for `Make`. Sub-signature of `Sig.G`.

`module Make (G : G) : sig ... end`

Provide a function for `k`-coloring a graph.