input: 
  def findGCD(a, b):
      """ Find the greatest common divisor (GCD) of two given 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)