我正在努力完成一个数学问题，该问题使用Python中的牛顿的guess和check方法来近似数字的平方根。用户应该输入一个数字，对该数字的初始猜测，以及他们想返回多少次才能检查答案。为了使事情变得更容易并了解Python（几个月前我才刚刚开始学习该语言），我将其分解为许多较小的函数。现在的问题是，我在调用每个函数并传递数字时遇到了麻烦。

这是我的代码，提供注释以帮助您（每个功能按使用顺序排列）：

# This program approximates the square root of a number (entered by the user)
# using Newton's method (guess-and-check). I started with one long function,
# but after research, have attempted to apply smaller functions on top of each
# other.
# * NEED TO: call functions properly; implement a counting loop so the
# goodGuess function can only be accessed the certain # of times the user
# specifies. Even if the - .001 range isn't reached, it should return.

# sqrtNewt is basically the main, which initiates user input.

def sqrtNewt():
    # c equals a running count initiated at the beginning of the program, to
    # use variable count.
    print("This will approximate the square root of a number, using a guess-and-check process.")
    x = eval(input("Please type in a positive number to find the square root of: "))
    guess = eval(input("Please type in a guess for the square root of the number you entered: "))
    count = eval(input("Please enter how many times would you like this program to improve your initial guess: ")) 
    avg = average(guess, x)
    g, avg = improveG(guess, x)
    final = goodGuess(avg, x)
    guess = square_root(guess, x, count)
    compare(guess, x)


# Average function is called; is the first step that gives an initial average,
# which implements through smaller layers of simple functions stacked on each
# other.
def average(guess, x) :
    return ((guess + x) / 2)

# An improvement function which builds upon the original average function.
def improveG(guess, x) :
    return average(guess, x/guess)

# A function which determines if the difference between guess X guess minus the
# original number results in an absolute vale less than 0.001. Not taking
# absolute values (like if guess times guess was greater than x) might result
# in errors
from math import *
def goodGuess(avg, x) :
    num = abs(avg * avg - x)
    return (num < 0.001)

# A function that, if not satisfied, continues to "tap" other functions for
# better guess outputs. i.e. as long as the guess is not good enough, keep
# improving the guess.
def square_root(guess, x, count) :
    while(not goodGuess(avg, x)):
        c = 0
        c = c + 1
        if (c < count):
            guess = improveG(guess, x)
        elif (c == count):
            return guess
        else :
            pass

# Function is used to check the difference between guess and the sqrt method
# applied to the user input.
import math
def compare(guess, x):
    diff = math.sqrt(x) - guess
    print("The following is the difference between the approximation") 
    print("and the Math.sqrt method, not rounded:", diff)

sqrtNewt()

当前，我收到此错误：g, avg = improveG(guess, x) TypeError: 'float' object is not iterable.
final函数使用猜测的最终迭代从数学平方根方法中减去，并返回总差。我什至这样做对吗？如果可以的话，可以提供建议的工作代码，并提供建议。同样，我是新手，因此对误解或明显的盲目的错误表示歉意。