How to use the pycountry.db function in pycountry

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):

    def __init__(self, **kw):
        if 'parent' in kw:
            kw['parent_code'] = kw['parent']
        else:
            kw['parent_code'] = None
        super(Subdivision, self).__init__(**kw)
        self.country_code = self.code.split('-')[0]

"""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):

    def __init__(self, **kw):
        if 'parent' in kw:
            kw['parent_code'] = kw['parent']
        else:
            kw['parent_code'] = None
        super(Subdivision, self).__init__(**kw)
        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