export declare abstract class Reply {
    abstract value: string | null;
    abstract isError(): this is ErrReply;
}
export declare class OkReply extends Reply {
    value: string | null;
    constructor(value: string | null);
    isError(): this is ErrReply;
}
export declare class ErrReply extends Reply {
    value: string | null;
    constructor(value: string | null);
    isError(): this is ErrReply;
    toError(): Error;
}