public static function EndsWithValidTldString( string &$stringToCheck, bool $convertUniCode = false ) : bool
   {

      if ( $convertUniCode ) { $stringToCheck = idnToASCII( $stringToCheck ); }

      return (bool) \preg_match(
         '~\.(' . static::DOUBLE_TLDS . '|' . static::KNOWN_FORMAT . ')\.?$~i',
         $stringToCheck
      );

   }