Check Leap Year in mysql

DELIMITER $$

DROP FUNCTION IF EXISTS `isLeapYear` $$
CREATE DEFINER=`root`@`192.168.10.116` FUNCTION `isLeapYear`(_year varchar(10)) RETURNS varchar(10) CHARSET latin1
BEGIN

declare tt varchar(10);

set tt = if(((_year % 4 = 0) AND ( (_year% 100 != 0) OR (_year % 400 = 0)))=1,'true','false');
return tt;

END $$

DELIMITER ;