function fetchVideo (id: number | string, fetchType: 'only-video', userId?: number): Bluebird<MVideoThumbnail>
function fetchVideo (id: number | string, fetchType: 'only-video-with-rights', userId?: number): Bluebird<MVideoWithRights>
function fetchVideo (id: number | string, fetchType: 'id' | 'none', userId?: number): Bluebird<MVideoIdThumbnail>
function fetchVideo (id: number | string, fetchType: 'only-video', userId?: number): Bluebird<MVideoThumbnail>
function fetchVideo (id: number | string, fetchType: 'only-video-with-rights', userId?: number): Bluebird<MVideoWithRights>
function fetchVideo (id: number | string, fetchType: 'id' | 'none', userId?: number): Bluebird<MVideoIdThumbnail>