How to use the @nakedobjects/services.HttpStatusCode.UnprocessableEntity function in @nakedobjects/services

const rejectAsNeedSelection = (action: Ro.ActionRepresentation | Ro.InvokableActionMember): ErrorWrapper | null => {
                if (this.isLocallyContributed(action)) {
                    if (selected.length === 0) {
                        const em = new Ro.ErrorMap({}, 0, Msg.noItemsSelected);
                        const rp = new ErrorWrapper(ErrorCategory.HttpClientError, HttpStatusCode.UnprocessableEntity, em);
                        return rp;
                    }
                }
                return null;
            };