def table_columns(table_name)
      {
        maxmind_geolite_city_blocks: %w[start_ip_num end_ip_num loc_id],
        maxmind_geolite_city_location: %w[loc_id country region city postal_code latitude longitude metro_code area_code],
        maxmind_geolite_country: %w[start_ip end_ip start_ip_num end_ip_num country_code country]
      }[table_name.to_sym]
    end
def table_columns(table_name)
      {
        maxmind_geolite_city_blocks: %w[start_ip_num end_ip_num loc_id],
        maxmind_geolite_city_location: %w[loc_id country region city postal_code latitude longitude metro_code area_code],
        maxmind_geolite_country: %w[start_ip end_ip start_ip_num end_ip_num country_code country]
      }[table_name.to_sym]
    end
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