old_contents: def compute_gcd(m, n):
      """Compute the greatest common divisor (GCD) by Euclid's Algorithm.
  
      Time complexity: O(m%n).
      """
      while m % n != 0:
          old_m = m
          old_n = n
          m = old_n
          n = old_m % old_n
      return n
  
new_contents: def gcd(m, n):
      """Greatest Common Divisor (GCD) by Euclid's Algorithm.
  
      Time complexity: O(m%n).
      """
      while n != 0:
          m, n = n, m % n
      return m
  
  
  def main():
      print(gcd(4, 2))
      print(gcd(2, 4))
  
      print(gcd(10, 4))
      print(gcd(4, 10))
  
      print(gcd(10, 1))
      print(gcd(1, 10))
  
  
  if __name__ == '__main__':
      main()
  
subject: Revise gcd algorithm