code: function(
      playlistId,
      positions,
      snapshotId,
      callback
    ) {
      return WebApiRequest.builder(this.getAccessToken())
        .withPath('/v1/playlists/' + playlistId + '/tracks')
        .withHeaders({ 'Content-Type': 'application/json' })
        .withBodyParameters({
          positions: positions,
          snapshot_id: snapshotId
        })
        .build()
        .execute(HttpManager.del, callback);
    }
docs: Remove tracks from a playlist by position instead of specifying the tracks' URIs.
  @param {string} playlistId The playlist's ID
  @param {int[]} positions The positions of the tracks in the playlist that should be removed
  @param {string} snapshot_id The snapshot ID, or version, of the playlist. Required
  @param {requestCallback} [callback] Optional callback method to be called instead of the promise.
  @returns {Promise|undefined} A promise that if successful returns an object containing a snapshot_id. If rejected,
  it contains an error object. Not returned if a callback is given.