input: 
  def findGCD(a: int, b: int) -> int: 
      """ Compute the Greatest Common Divisor (GCD) of two numbers.
      >>> findGCD(1000, 500)
      500
      >>> findGCD(20, 30)
      10
      """
      if (b == 0): 
          return a
      return findGCD(b, a % b)
  
  a = 1000
  b = 500
  print("GCD of numbers is: ", findGCD(a, b))
  
output:     if (b == 0): 
          return a
      return findGCD(b, a % b)