method virtual assoc : 'a -> 'bmethod virtual delkey : 'a -> 'omethod find_opt : 'a -> 'b optionmethod haskey : 'a -> boolmethod replkey : ('a * 'b) -> 'omethod virtual keys : 'a listmethod apply : 'a -> ('b -> 'b) -> 'omethod apply_with_default : 'a -> ('b -> 'b) -> (unit -> 'b) -> 'omethod apply_with_default2 : 'a -> ('b -> 'b) -> (unit -> 'b) -> unit