input: Write a python function to check if the sum of two given prime numbers is also a prime number.
  assert check_prime_pair_addition(23, 59) == 82
  assert check_prime_pair_addition(2, 3) == 5
  assert check_prime_pair_addition(11, 13) == 24
output: def check_prime_pair_addition(a, b):
      def is_prime(n):
          if n <= 1:
              return False
          if n <= 3:
              return True
          if n % 2 == 0 or n % 3 == 0:
              return False
          i = 5
          while i * i <= n:
              if n % i == 0 or n % (i + 2) == 0:
                  return False
              i += 6
          return True
  
      if is_prime(a) and is_prime(b):
          return a + b
      return None