Pythonの：AssertionErrorが

まず、それは私がテストを必要とするコードです：Pythonの：AssertionErrorが

class ParserError(Exception): 
    pass 

class Sentence(object): 

    def __init__(self, subject, verb, object): 
self.subject = subject [1] 
     self.verb = verb[1] 
     self.object = object[1] 

def peek(word_list): 
    if word_list: 
     word = word_list[0] 
     return word[0] 
    else: 
     return None 

def match(word_list, expecting): 
if word_list: 
     word = word_list.pop(0) 

     if word[0] == expecting: 
      return word 
     else: 
      return None 
    else: 
     return None 

def skip (word_list, word_type): 
    while peek(word_list) == word_type: 
     match(word_list, word_type) 

def parse_verb(word_list): 
    skip(word_list, 'stop') 

    if peek(word_list) == 'verb': 
     return match(word_list, 'verb') 
    else: 
     raise ParserError("Expected a verb next.") 


def parse_object(word_list): 
    skip(word_list,'stop') 
    next = peek(word_list) 

    if next == 'noun': 
     return match(word_list, 'noun') 
    if next == 'direction': 
     return match(word_list, 'direction') 
    else: 
     raise ParserError('Expected a noun or direction next.') 

def parse_subject(word_list, subj): 
    verb = parse_verb(word_list) 
    obj = parse_object(word_list) 

    return Sentence(subj, verb, obj) # 执行 class Sentence 

def parse_sentence(word_list): 
    skip(word_list, 'stop') 

    start = peek(word_list) 

    if start == 'noun': 
     subj = match(word_list, 'noun') 
     return parse_sentence(word_list, subj) 
    elif start == 'verb': 
     # assume the subject is the player then 
     return parse_subject(word_list, ('noun', 'player')) 
    else: 
     raise ParserError("Must start with subject, object, or verb not: %s" % start)

私が入力されたリストは、[（ '動詞'、 '味'）、（ '方向'、 '良い'）です、（ 'noun'、 'pizza'）] このリストの最初の値は（ '動詞'、 '味'）で、そのword_typeは '動詞'で、私のコーディングで与えたword_typeに合致しますが、エラーが発生しました AssertionError：None！= '動詞' 私はそれが不合理だと思います。

def test_skip(): 
    skipA = skip([('verb','taste'),('direction','good'),('noun','pizza')], 'verb') 
    assert_equal(skipA, 'verb') 
# assert_equal(skipA, None)

出典

2017-08-29 Electro01