python报错：urllib.error.HTTPError: HTTP Error 404: Not Found 怎么解决请教大神

代码如下：

import sys
import random
from urllib.request import urlopen
WORD_URL = "http://learncodethehardway.org/word.txt"
WORDS = []
PHRASES = {
    "class %%%(%%%):":
        "Make a class named %%% that is-a %%%.",
    "class %%%(object):\n\tdef __init__(self,***)":
        "class %%% has-a __init__ that takes self and *** params.",
    "class %%%(object): \n\tdef ***(self, @@@)":
        "class %%% has-a function *** that takes self and @@@ params.",
    "*** = %%%()":
        "Set *** to an instance of class %%%.",
    "***.*** = @@@":
        "From *** get the *** function, call it with params self, @@@,",
    "***.*** = '***'":
        "From *** get the *** attribute and  set it to '***'."
}
if len(sys.argv) == 2 and sys.argv[1] == "english":
    PHRASE_FIRST = True
else:
    PHRASE_FIRST = False

for word in urlopen(WORD_URL).readlines():
    WORDS.append(str(word.strip(), encoding='utf-8'))
    
def convert(snippet, phrase):
    class_names = [w.capitalize() for w in random.sample(WORDS, snippet.count("%%%"))]     
    other_names = random.sample(WORDS, snippet.count("***"))         
  results = []
    param_names = []
    for i in range(0, snippet.count('@@@')):
        param_count = random.randint(1, 3)    
        param_names.append(', '.join(random.sample(WORDS, param_count)))        
    for sentence in snippet, phrase:
        result = sentence[:]
        for word in class_names:
            result = result.replace('%%%', word, 1)     
        for word in other_names:
            result = result.replace('***', word, 1)     
        for word in param_names:
            result = result.replace('@@@', word, 1)     
        results.append(result)
    return results

try:
    while True:
        snippets = list(PHRASES.keys())    
        random.shuffle(snippets)        
        for snippet in snippets:
            phrase = PHRASES[snippet]      
            question, answer = convert(snippet, phrase)   
            if PHRASE_FIRST:
                question, answer = answer, question
            print(question)
            input("> ")
            print(f"ANSWER:  {answer}\n\n")

  except EOFError:
      print("\nBye")

报错信息：

Traceback (most recent call last):
  File "E:/python/笨办法学python/面向对象术语/ex41.py", line 30, in <module>
    for word in urlopen(WORD_URL).readlines():
  File "D:\pycharm\lib\urllib\request.py", line 222, in urlopen
    return opener.open(url, data, timeout)
  File "D:\pycharm\lib\urllib\request.py", line 531, in open
    response = meth(req, response)
  File "D:\pycharm\lib\urllib\request.py", line 641, in http_response
    'http', request, response, code, msg, hdrs)
  File "D:\pycharm\lib\urllib\request.py", line 563, in error
    result = self._call_chain(*args)
  File "D:\pycharm\lib\urllib\request.py", line 503, in _call_chain
    result = func(*args)
  File "D:\pycharm\lib\urllib\request.py", line 755, in http_error_302
    return self.parent.open(new, timeout=req.timeout)
  File "D:\pycharm\lib\urllib\request.py", line 531, in open
    response = meth(req, response)
  File "D:\pycharm\lib\urllib\request.py", line 641, in http_response
    'http', request, response, code, msg, hdrs)
  File "D:\pycharm\lib\urllib\request.py", line 569, in error
    return self._call_chain(*args)
  File "D:\pycharm\lib\urllib\request.py", line 503, in _call_chain
    result = func(*args)
  File "D:\pycharm\lib\urllib\request.py", line 649, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 404: Not Found