Formatter::getNationalPrefixFormattingRule

static function getNationalPrefixFormattingRule($format, $countryMetadata)
{
	if(isset($format['nationalPrefixFormattingRule']))
	{
		return $format['nationalPrefixFormattingRule'];
	}
	else
	{
		$countryCode = $countryMetadata['countryCode'];
		$countriesForCode = MetadataProvider::getInstance()->getCountriesByCode($countryCode);
		$mainCountry = $countriesForCode[0];
		$mainCountryMetadata = MetadataProvider::getInstance()->getCountryMetadata($mainCountry);
		return $mainCountryMetadata['nationalPrefixFormattingRule'] ?? '';
	}
}