Почему не сходятся ответы?

Вот такой код:

 def average_word_length(filename): 
    # Write code here     
    f = open(filename) 
    s = f.read() 
    print(s) 
    punctuation = '!?\'",.' 
    spisok = [] 
    for char in punctuation: 
        s = s.replace(char, '')
'''было ранее вместо двух строк выше, но результат тот же
    for i in s: 
        if i in punctuation: 
            s = s.replace(i, '')'''
    spisok1 = s.split() 
    print(spisok1) 
    for k in spisok1: 
        spisok.append(len(k)) 
     
    return round(sum(spisok) / len(spisok), 2) 

При тексте в передаваемом файле:

The quick brown fox jumps over the lazy dog. The dog barks, and the fox runs away.

ответ 3.71, который совпадает с верным

при тексте:

Hello there! How are you today? I hope you're doing well. Let's learn about file handling in Python. File handling is an important topic in programming.

мой ответ 4.62, а правильный 4.29

при тексте:

Programming is fun. You can create all sorts of applications with code. From games to utilities, programming empowers creativity. Don't be afraid to make mistakes and learn!

мой ответ 5.37, а правильный 5.1

само задание:

Write a function named average_word_length which gets a filename as argument and returns the average word length (rounded to two decimal points) in the file.

For example,

If input1.txt contains:

The quick brown fox jumps over the lazy dog. The dog barks, and the fox runs away.

Note: remove any punctuation!

подсказки:

Remove the characters !, ?, ', ", ,, . from the words.

Use round(res, 2) function to round res to two decimal points,