How to use the pycountry.db.Database function in pycountry

self.country_code = self.code.split('-')[0]
        if self.parent_code is not None:
            self.parent_code = '%s-%s' % (self.country_code, self.parent_code)

    @property
    def country(self):
        return countries.get(alpha_2=self.country_code)

    @property
    def parent(self):
        if not self.parent_code:
            return None
        return subdivisions.get(code=self.parent_code)


class Subdivisions(pycountry.db.Database):

    # Note: subdivisions can be hierarchical to other subdivisions. The
    # parent_code attribute is related to other subdivisons, *not*
    # the country!

    data_class_base = Subdivision
    data_class_name = 'Subdivision'
    no_index = ['name', 'parent_code', 'parent', 'type']
    root_key = '3166-2'

    def _load(self, *args, **kw):
        super(Subdivisions, self)._load(*args, **kw)

        # Add index for the country code.
        self.indices['country_code'] = {}
        for subdivision in self:

# results the negative value allows us to sort reversely on the
            # points but ascending on the country code.
            for x in sorted(results.items(),
                            key=lambda x: (-x[1], x[0]))]
        return results


class HistoricCountries(ExistingCountries):
    """Provides access to an ISO 3166-3 database
    (Countries that have been removed from the standard)."""

    data_class_name = 'Country'
    root_key = '3166-3'


class Scripts(pycountry.db.Database):
    """Provides access to an ISO 15924 database (Scripts)."""

    data_class_name = 'Script'
    root_key = '15924'


class Currencies(pycountry.db.Database):
    """Provides access to an ISO 4217 database (Currencies)."""

    data_class_name = 'Currency'
    root_key = '4217'


class Languages(pycountry.db.Database):
    """Provides access to an ISO 639-1/2T/3 database (Languages)."""

class Scripts(pycountry.db.Database):
    """Provides access to an ISO 15924 database (Scripts)."""

    data_class_name = 'Script'
    root_key = '15924'


class Currencies(pycountry.db.Database):
    """Provides access to an ISO 4217 database (Currencies)."""

    data_class_name = 'Currency'
    root_key = '4217'


class Languages(pycountry.db.Database):
    """Provides access to an ISO 639-1/2T/3 database (Languages)."""

    no_index = ['status', 'scope', 'type', 'inverted_name', 'common_name']
    data_class_name = 'Language'
    root_key = '639-3'


class LanguageFamilies(pycountry.db.Database):
    """Provides access to an ISO 639-5 database
       (Language Families and Groups)."""

    data_class_name = 'LanguageFamily'
    root_key = '639-5'


class Subdivision(pycountry.db.Data):

class HistoricCountries(ExistingCountries):
    """Provides access to an ISO 3166-3 database
    (Countries that have been removed from the standard)."""

    data_class_name = 'Country'
    root_key = '3166-3'


class Scripts(pycountry.db.Database):
    """Provides access to an ISO 15924 database (Scripts)."""

    data_class_name = 'Script'
    root_key = '15924'


class Currencies(pycountry.db.Database):
    """Provides access to an ISO 4217 database (Currencies)."""

    data_class_name = 'Currency'
    root_key = '4217'


class Languages(pycountry.db.Database):
    """Provides access to an ISO 639-1/2T/3 database (Languages)."""

    no_index = ['status', 'scope', 'type', 'inverted_name', 'common_name']
    data_class_name = 'Language'
    root_key = '639-3'


class LanguageFamilies(pycountry.db.Database):
    """Provides access to an ISO 639-5 database

__version__ = 'n/a'
    def resource_filename(package_or_requirement, resource_name):
        return os.path.join(os.path.dirname(__file__), resource_name)


LOCALES_DIR = resource_filename('pycountry', 'locales')
DATABASE_DIR = resource_filename('pycountry', 'databases')


def remove_accents(input_str):
    # Borrowed from https://stackoverflow.com/a/517974/1509718
    nfkd_form = unicodedata.normalize('NFKD', input_str)
    return u"".join([c for c in nfkd_form if not unicodedata.combining(c)])


class ExistingCountries(pycountry.db.Database):
    """Provides access to an ISO 3166 database (Countries)."""

    data_class_name = 'Country'
    root_key = '3166-1'

    def search_fuzzy(self, query):
        query = remove_accents(query.strip().lower())

        # A country-code to points mapping for later sorting countries
        # based on the query's matching incidence.
        results = {}

        def add_result(country, points):
            results.setdefault(country.alpha_2, 0)
            results[country.alpha_2] += points