public function out_date( $format = NULL )
	{
		if( NULL == $format ) {
			$format = self::get_default_date_format();
		}
		echo $this->format( $format );
	}

	public function out_time( $format = NULL )
	{
		if( NULL == $format ) {
			$format = self::get_default_time_format();
		}
		echo $this->format( $format );
	}