擅长:python、mysql、java
<p><code>LazyUser</code>是描述符类。根据<a href="http://docs.python.org/reference/datamodel.html#invoking-descriptors" rel="nofollow noreferrer">documentation</a>它只能是类属性而不是实例一:</p>
<blockquote>
<p>For instance, <code>a.x</code> has a lookup chain starting with <code>a.__dict__['x']</code>, then <code>type(a).__dict__['x']</code>, and continuing through the base classes of <code>type(a)</code> excluding metaclasses.</p>
</blockquote>