xcode 6.1 iOS 8.1 NSLocale displayNameForKey NSLocaleIdentifier retorno nulo

- (NSString *)countryNameByCode:(NSString*)countryCode
{
    NSString *identifier = [NSLocale localeIdentifierFromComponents:@{NSLocaleCountryCode: countryCode}];
    NSString *countryName = [[NSLocale currentLocale] displayNameForKey:NSLocaleIdentifier value:identifier];

    return countryName;
}

Isso retornounil. Por quê?

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