+
+(* like List.assoc but returns all bindings *)
+val list_assoc_all: 'a -> ('a * 'b) list -> 'b list
+
+val rm_assoc_option : 'a -> ('a * 'b) list -> 'b option * ('a * 'b) list
+
+val rm_assoc_assert : 'a -> ('a * 'b) list -> 'b * ('a * 'b) list
+
+val clusters : (int -> int list) -> int list -> int list list