rightmost() {
    checkPossibilityOfDynamicTraversal('rightmost', this.solvedPath);

    const last = +this.solvedPath[this.solvedPath.length - 1];

    if (isNaN(last))
      throw Error(
        'Baobab.Cursor.rightmost: cannot go right on a non-list type.');

    const list = this.up()._get().data;

    return this.tree
      .select(this.solvedPath.slice(0, -1).concat(list.length - 1));
  }
Method returning the rightmost sibling node of the cursor if this one is
pointing at a list.

@return {Baobab} - The rightmost sibling cursor.