input: Write a function to find the GCD of two numbers. The function should take two parameters, a and b, and return the GCD of these numbers. If either number is zero, the function should return the other number.
  assert findGCD(1000, 500)==500
  assert findGCD(9, 12)==3
  assert findGCD(56, 98)==14
  assert findGCD(10, 0)==10
  assert findGCD(0, 7)==7
output: def findGCD(a, b):
      while b != 0:
          a, b = b, a % b
      return a