add_island_cols         Add island classification columns to a data
                        frame
aruba                   A.R.U.B.A.: Annotated Reference for Under-coded
                        Border Areas
classify                Classify countries and territories
island_lookup           Look up rows in the islands reference list
islands                 Reference list of countries and territories
                        with small-island classifications
small_islands           Return a filtered subset of small-island states
                        and territories
