What does classmethod do in this code?
<p>In django.utils.tree.py:</p>

<pre><code>def _new_instance(cls, children=None, connector=None, negated=False):
        obj = Node(children, connector, negated)
        obj.__class__ = cls
        return obj
    _new_instance = classmethod(_new_instance)
</code></pre>

<p>I don't know what <code>classmethod</code> does in this code sample. Can someone explain what it does and how to use it?</p>
