擅长:python、mysql、java
<p>我还没有亲自尝试过,但是根据引用<strong>返回了\u表达式</strong><a href="https://developers.google.com/appengine/docs/python/search/queryoptionsclass?hl=en#QueryOptions_returned_expressions" rel="nofollow">should be iterable</a>。另请参见<a href="https://developers.google.com/appengine/docs/python/search/options?hl=en" rel="nofollow">Query and Sorting Options</a>上的示例并将其更改为</p>
<pre><code>returned_expressions=[FieldExpression('content_snippet', snippet)]
</code></pre>