擅长:python、mysql、java
<p>你列个单子!太好了!现在对它执行一个不返回任何内容的方法。太好了!让我们看看发生了什么:</p>
<pre>
Make a list, return the list.
Perform an immediate method on the list.
Extend the list, (Extending does not return anything)
Now that everything is done, return the final result, which is None.
</pre>
<p>因此,请保存它并分步骤执行:</p>
<pre><code>VIDEO_COLUMNS = list(DEFAULT_COLUMNS)
VIDEO_COLUMNS.extend([
('Time Watched', 'time_watched'),
('Video Length', 'video_length')])
</code></pre>