anchor.diff:    ["msg", String msg]
     |> Map.ofList
     |> Object
  -  |> jsonWebPart fWebpart
  +  |> json fWebpart
   
   let badRequest msg = 
     error RequestErrors.BAD_REQUEST msg
  
positive.code: let internalError =
    error ServerErrors.INTERNAL_ERROR "something went wrong"
  
  let inline ok< ^a when (^a or ToJsonDefaults) 
                : (static member ToJson: ^a -> Json<unit>)> (data : ^a) =
    data |> Json.serialize |> jsonWebPart Successful.OK
negative.code: 
  let contentType = "application/json; charset=utf-8"
  
  let json fWebpart json = 
    json
    |> Json.format
    |> fWebpart
  