from pandas import read_csv, concat, DataFrame
from iso3166 import countries


def select_columns() -> [DataFrame]:
    min_year = 2010
    fields = ["POLITICAL_UNIT", "WGMS_ID", "YEAR"]
    iter_csv = read_csv(
        "../../Assets/WGMS-FoG-2019-12-D-CHANGE.csv",
        skipinitialspace=True,
        usecols=fields,
        iterator=True,
        chunksize=100,
    )
    data = concat([chunk[chunk["YEAR"] > min_year] for chunk in iter_csv])
    return data