input: Write a function to find the GCD of two numbers using the Euclidean algorithm. If either number is zero, return the non-zero number as the GCD. If both numbers are zero, raise an error.
  assert findGCD(1000, 500) == 500
  assert findGCD(9, 28) == 1
  assert findGCD(0, 5) == 5
  assert findGCD(36, 48) == 12
  assert findGCD(0, 0) == "Both numbers cannot be zero"
output: def findGCD(a, b):
      if a == 0 and b == 0:
          raise ValueError("Both numbers cannot be zero")
      while b != 0:
          a, b = b, a % b
      return a