擅长:python、mysql、java
<p>你必须分配实例的属性。这是正确的代码:</p>
<pre><code>class Apple():
def __init__(self, color, variety_name, size, place_grown):
self.color = color
self.variety_name = variety_name
self.size = size
self.place_grown = place_grown
</code></pre>
<p>更改格式:</p>
^{pr2}$
<p>此处将<code>self.variety</code>改为<code>self.variety_name</code>:</p>
<pre><code>def for_pies(self):
return self.variety in ["Granny Smith", "Braeburn", "Golden Delicious"]
</code></pre>
<p>然后你可以写下以下作业:</p>
<pre><code>ap2 = Apple("green","Granny Smith","large","Sydney, Australia")
print ap2 # Should print: A large green apple of the Granny Smith variety, grown in Sydney, Australia
print ap2.for_pies() # should print True
ap3 = Apple("red","Mystery variety", "small","Michigan")
print ap3.for_pies() # should print False
print ap3 # should print: A small red apple of the Mystery variety variety, grown in Michigan
</code></pre>