input: Write a python function to check if a number is prime using a class.
  assert is_prime(2) == True
  assert is_prime(3) == True
  assert is_prime(4) == False
  assert is_prime(17) == True
  assert is_prime(20) == False
output: def is_prime(num):
      class PrimeChecker:
          def __init__(self, number):
              self.number = number
  
          def check(self):
              if self.number <= 1:
                  return False
              if self.number <= 3:
                  return True
              if self.number % 2 == 0 or self.number % 3 == 0:
                  return False
              i = 5
              while i * i <= self.number:
                  if self.number % i == 0 or self.number % (i + 2) == 0:
                      return False
                  i += 6
              return True
  
      return PrimeChecker(num).check()