declare module 'deepcopy'; declare namespace deepcopy { type DeepcopyCustomizerValueType = 'Object'; type DeepcopyCustomizer = ( value: T, valueType: DeepcopyCustomizerValueType) => T; interface DeepcopyOptions { customizer: DeepcopyCustomizer; } export function deepcopy( value: T, options?: DeepcopyOptions | DeepcopyCustomizer): T; }