src/TimeType.php
public static function checkLeapYear($year)
    {
        $year = Cast::_Int($year);

        if ($year % 4 !== 0) {
            return false;
        } elseif ($year % 100 !== 0) {
            return true;
        } elseif ($year % 400 !== 0) {
            return false;
        } elseif ($year === 0) {
            return false;
        }

        return true;
    }
public static function checkLeapYear($year)
    {
        $year = Cast::_Int($year);

        if ($year % 4 !== 0) {
            return false;
        } elseif ($year % 100 !== 0) {
            return true;
        } elseif ($year % 400 !== 0) {
            return false;
        } elseif ($year === 0) {
            return false;
        }

        return true;
    }
True if it's a leap year

@param  int  $year
@return bool