擅长:python、mysql、java
<p>试试这个:</p>
<pre><code>def allChildren(self, l = None):
if(l==None):
l = list()
l.append(self)
for child in self.children:
l = child.allChildren(l)
return l
</code></pre>
<p>请查看<a href="https://stackoverflow.com/questions/1651154/why-are-default-arguments-evaluated-at-definition-time-in-python">this answer</a>进行解释。在</p>