中文版的《“笨辦法”學Python》書中給出的程式碼ex41.py存在縮排問題，由於Python根據縮排來區分程式碼塊，因此少一個縮排就牛頭不對馬嘴了……

原書中第47行到第59行的部分需要再加一個縮排，程式碼才能正常執行，附上正確程式碼：

import random
from urllib import urlopen
import sys

WORD_URL = "http://learncodethehardway.org/words.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 *** parameters.",
    "class %%%(object):\n\tdef ***(self,@@@)":
        "class %%% has-a function named *** that takes self and @@@ parameters.",
    "*** = %%%()":
        "Set *** to an instance of class %%%.",
    "***.***(@@@)":
        "From *** get the *** functions,and call it with parameters self,@@@.",
    "***.*** = '***'":
        "From *** get the *** attribute and set it to '***'."

}

#do they want to drill phrases first
PHRASE_FIRST = False
if len(sys.argv) == 2 and sys.argv[1] == "english":
    PHRASE_FIRST = True

#load up the words from the website
for word in urlopen(WORD_URL).readline():
    WORDS.append(word.strip())


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[:]

        #fake class names
        for word in class_names:
            result = result.replace("%%%", word, 1)

        #fake other names
        for word in other_names:
            result = result.replace("***", word, 1)

        #fake parameter lists
        for word in param_names:
            result = result.replace("@@@", word, 1)

        results.append(result)

    return results


# keep going until they hit CTRL-D
try:
    while True:
        snippets = 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


            raw_input("> ")
            print "ANSWER:   %s\n\n" % answer
except EOFError:
    print "\nBye"