errors

File "canopy_store.ml", line 122, characters 37-39:
Error: This expression has type
         Store.key ->
         (unit -> string Lwt.t) ->
         ([> `Article of C.content_t
           | `Config of string
           | `Raw of string * Ptime.t
           | `Redirect of Uri.t ]
          as 'a)
         Canopy_utils.KeyMap.t -> 'a Canopy_utils.KeyMap.t Lwt.t
       but an expression was expected of type
         Store.key -> Store.value Lwt.t -> 'b -> 'b Lwt.t
       Type unit -> string Lwt.t is not compatible with type
         Store.value Lwt.t 
Command exited with code 2.