class CityNameMapping(object):
    CITY_NAME_MAPPING = {}

    with open('data/city.csv', 'r') as file:
        data = file.read()
        if not data.startswith("#"):
            city_entry = data.split('t')
            CITY_NAME_MAPPING[city_entry[1]] = city_entry[0]

    @classmethod
    def get_mapping(cls, city):
        if city in cls.CITY_NAME_MAPPING:
            return cls.CITY_NAME_MAPPING[city]
        else:
            print("No city name found: {} ".format(city))
            return None

Nagoya  名古屋市