`val add : ('a, 'b) t -> key:'a -> data:'b -> unit`
`val replace : ('a, 'b) t -> key:'a -> data:'b -> unit`
`val iter : f:(key:'a -> data:'b -> unit) -> ('a, 'b) t -> unit`
`val for_all : f:(key:'a -> data:'b -> bool) -> ('a, 'b) t -> bool`
`val map : f:(key:'a -> data:'b -> 'c) -> ('a, 'b) t -> ('a, 'c) t`
`val map_inplace : f:(key:'a -> data:'b -> 'b) -> ('a, 'b) t -> unit`
`val filter : f:('a -> bool) -> ('key, 'a) t -> ('key, 'a) t`
`val filter_inplace : f:('a -> bool) -> ('key, 'a) t -> unit`
`val filteri : f:(key:'key -> data:'a -> bool) -> ('key, 'a) t -> ('key, 'a) t`
`val filteri_inplace : f:(key:'key -> data:'a -> bool) -> ('key, 'a) t -> unit`
`val filter_map : f:(key:'key -> data:'a -> 'b option) -> ('key, 'a) t -> ('key, 'b) t`
`val filter_map_inplace : f:(key:'key -> data:'a -> 'a option) -> ('key, 'a) t -> unit`
`val fold : f:(key:'a -> data:'b -> 'c -> 'c) -> ('a, 'b) t -> init:'c -> 'c`
`val exists : f:(key:'a -> data:'b -> bool) -> ('a, 'b) t -> bool`
`val modify : key:'a -> f:('b -> 'b) -> ('a, 'b) t -> unit`
`val modify_def : default:'b -> key:'a -> f:('b -> 'b) -> ('a, 'b) t -> unit`
`val modify_opt : key:'a -> f:('b option -> 'b option) -> ('a, 'b) t -> unit`
`val merge : f:('a -> 'b option -> 'c option -> 'd option) -> left:('a, 'b) t -> right:('a, 'c) t -> ('a, 'd) t`
`val merge_all : f:('a -> 'b list -> 'c list -> 'd list) -> left:('a, 'b) t -> right:('a, 'c) t -> ('a, 'd) t`