input: Write a python function to check if all numbers in a list are prime numbers.
  assert is_prime([2, 3, 5, 7, 11, 13]) == True
  assert is_prime([2, 4, 6, 8, 10, 12]) == False
  assert is_prime([17, 19, 23, 29]) == True
  assert is_prime([15, 21, 25, 27]) == False
output: def is_prime(numbers):
      def check_prime(n):
          if n <= 1:
              return False
          for i in range(2, int(n ** 0.5) + 1):
              if n % i == 0:
                  return False
          return True
      
      return all(check_prime(num) for num in numbers)