nl: get a read-only list of all the items on the top shelf concode_field_sep List<Potion> topShelf concode_elem_sep List<Potion> bottomShelf concode_elem_sep Logger LOGGER concode_field_sep List<Potion> getBottomShelf concode_elem_sep void enumerate concode_elem_sep void fillShelves
code: List < Potion > function ( ) { return Collections . unmodifiableList ( this . topShelf ) ; }