Exercise: leap year

Write a function is_leap(year) that returns True if the year is a leap year and False if it is not. A year is a leap year if one of these rules holds:

• the year is divisible by 4 but not by 100;
• the year is divisible by 400.

• is_leap(2024) → True
• is_leap(1900) → False
• is_leap(2000) → True

Constraints: year is an integer from 1 to 9999. The tests check the answer with got is True or got is False: it demands exactly True or False, so the number 1 in place of True does not pass.

Do not add extra imports unless the task says so explicitly.