input: def findGCD(a: int, b: int) -> int:
      """Find the greatest common divisor (GCD) of two numbers using the Euclidean algorithm.
      >>> findGCD(1000, 500)
      500
      >>> findGCD(48, 18)
      6
      """
      if b == 0:
          return a
      return findGCD(b, a % b)
output:     if b == 0:
          return a
      return findGCD(b, a % b)