CODE EXAMPLE FOR PYTHON

leap year formula

$day = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];
$year = 2021;

if (($year % 4 == 0 && $year % 100 != 0) || ($year % 400 == 0)) {
  $day = [ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 ];
  echo "This is leap year - get 366 day";
  
} else {
   echo "This is NOT leap year - get ONLY 365 day";
}