module type Accessors : sig ... end
type ('key, 'z) create_options_without_hashable
= ('key, unit, 'z) Base.Hashtbl_intf.create_options_without_hashable
type ('key, 'z) create_options_with_hashable_required
= ('key, unit, 'z) Base.Hashtbl_intf.create_options_with_hashable
type ('key, 'z) create_options_with_first_class_module
= ('key, unit, 'z) Base.Hashtbl_intf.create_options_with_first_class_module
module type Creators : sig ... end