static function IsDstNorthAmerica($timestamp = null)
	{
		if (!$timestamp) $timestamp = time();
		return $timestamp > self::DstStartNorthAmerica() && $timestamp < self::DstEndNorthAmerica();
	}
static function IsDstNorthAmerica($timestamp = null)
	{
		if (!$timestamp) $timestamp = time();
		return $timestamp > self::DstStartNorthAmerica() && $timestamp < self::DstEndNorthAmerica();
	}
static function IsDstNorthAmerica ( $ timestamp = null ) { if ( ! $ timestamp ) $ timestamp = time ( ) ; return $ timestamp > self :: DstStartNorthAmerica ( ) && $ timestamp < self :: DstEndNorthAmerica ( ) ; }
Return true if the date is within the DST observation range for North America
@param int $timestamp (if not provided then the current server time will be used)
Return true if the date is within the DST observation range for North America