Implement a class that checks if a year is a leap year.

All the following rules must be satisfied:

• Is NOT a leap year if NOT divisible by 4
• Is a leap year if divisible by 4
• Is a leap year if divisible by 400
• Is NOT a leap year if divisible by 100 but NOT by 400

Examples:

• 1997 is NOT a leap year (not divisible by 4)
• 1996 is a leap year (divisible by 4)
• 1600 is a leap year (divisible by 400)
• 1800 is NOT a leap year (divisible by 4, divisible by 100, NOT divisible by 400)