Python求解平方根的方法

#!/usr/bin/python
def sqrt_iter(guess,x):
  if(good_enough(guess, x)):
    print guess
  else:
    sqrt_iter(improve(guess, x),x)
def improve(guess, x):
  return average(guess, x/guess)
def average(x,y):
   return (x+y)/2
def good_enough(guess,x):
  if(abs(guess * guess -x) < 0.0001):
    return True
  else:
    return False
def sqrt_oliver(x):
  sqrt_iter(1.0,x)
sqrt_oliver(5)