`val add : ('a, 'b, [> `Write ]) t -> key:'a -> data:'b -> unit`
`val replace : ('a, 'b, [> `Write ]) t -> key:'a -> data:'b -> unit`
`val iter : f:(key:'a -> data:'b -> unit) -> ('a, 'b, [> `Read ]) t -> unit`
`val for_all : f:(key:'a -> data:'b -> bool) -> ('a, 'b, [> `Read ]) t -> bool`
`val map : f:(key:'a -> data:'b -> 'c) -> ('a, 'b, [> `Read ]) t -> ('a, 'c, _) t`
`val map_inplace : f:(key:'a -> data:'b -> 'b) -> ('a, 'b, [> `Write ]) t -> unit`
`val filter : f:('a -> bool) -> ('key, 'a, [> `Read ]) t -> ('key, 'a, _) t`
`val filter_inplace : f:('a -> bool) -> ('key, 'a, [> `Write ]) t -> unit`
`val filteri : f:(key:'key -> data:'a -> bool) -> ('key, 'a, [> `Read ]) t -> ('key, 'a, _) t`
`val filteri_inplace : f:(key:'key -> data:'a -> bool) -> ('key, 'a, [> `Write ]) t -> unit`
`val filter_map : f:(key:'key -> data:'a -> 'b option) -> ('key, 'a, [> `Read ]) t -> ('key, 'b, _) t`
`val filter_map_inplace : f:(key:'key -> data:'a -> 'a option) -> ('key, 'a, [> `Write ]) t -> unit`
`val fold : f:(key:'a -> data:'b -> 'c -> 'c) -> ('a, 'b, [> `Read ]) t -> init:'c -> 'c`
`val exists : f:(key:'a -> data:'b -> bool) -> ('a, 'b, [> `Read ]) t -> bool`
`val merge : f:('key -> 'a option -> 'b option -> 'c option) -> left:('key, 'a, [> `Read ]) t -> right:('key, 'b, [> `Read ]) t -> ('key, 'c, _) t`
`val merge_all : f:('key -> 'a list -> 'b list -> 'c list) -> left:('key, 'a, [> `Read ]) t -> right:('key, 'b, [> `Read ]) t -> ('key, 'c, _) t`