How to use the iso3166.Country function in iso3166

def _apply(self, value):
        # Lazy-load dependencies to reduce memory usage when this
        # filter is not used in a project.
        from iso3166 import (
            countries_by_alpha2,
            countries_by_alpha3,
            Country as CountryType,
        )

        value = self._filter(value, Type(string_types + (CountryType,)))

        if self._has_errors:
            return None

        if isinstance(value, CountryType):
            return value

        search_functions = {
            2: countries_by_alpha2,
            3: countries_by_alpha3,
        }

        try:
            return search_functions[len(value)][value.upper()]
        except KeyError:
            return self._invalid_value(value, self.CODE_INVALID, exc_info=True)

from ...icon_constant import PRepGrade, PRepStatus, PenaltyReason, Revision, PRepFlag
from ...utils.msgpack_for_db import MsgPackForDB

if TYPE_CHECKING:
    from iconservice.base.address import Address


class PRepDictType(Enum):
    FULL = auto()  # getPRep
    ABRIDGED = auto()  # getPReps


class PRep(Sortable):
    PREFIX: bytes = b"prep"
    _VERSION: int = 2
    _UNKNOWN_COUNTRY = iso3166.Country("Unknown", "ZZ", "ZZZ", "000", "Unknown")

    class Index(IntEnum):
        VERSION = 0

        # Version: 0
        ADDRESS = auto()
        STATUS = auto()
        GRADE = auto()
        NAME = auto()
        COUNTRY = auto()
        CITY = auto()
        EMAIL = auto()
        WEBSITE = auto()
        DETAILS = auto()
        P2P_ENDPOINT = auto()
        IREP = auto()

def _apply(self, value):
        # Lazy-load dependencies to reduce memory usage when this
        # filter is not used in a project.
        from iso3166 import (
            countries_by_alpha2,
            countries_by_alpha3,
            Country as CountryType,
        )

        value = self._filter(value, Type(string_types + (CountryType,)))

        if self._has_errors:
            return None

        if isinstance(value, CountryType):
            return value

        search_functions = {
            2: countries_by_alpha2,
            3: countries_by_alpha3,
        }

        try:
            return search_functions[len(value)][value.upper()]
        except KeyError:
            return self._invalid_value(value, self.CODE_INVALID, exc_info=True)