type Argument<T> = T extends (arg: infer U, callback: infer X) => unknown ? U : unknown;
type Callback<T> = T extends (arg: infer U, callback: infer X) => unknown ? X : unknown;
export declare function promisify<V, S extends (arg: Argument<S>, callback: Callback<S>) => void>(fn: S): (arg: Argument<S>) => Promise<V>;
export default promisify;