Is there any case where len(someObj) does not call someObj's __len__ function?
<p>Is there any case where len(someObj) does not call someObj's <code>__len__</code> function?</p>

<p>I recently replaced the former with the latter in a (sucessful) effort to speed up some code.  I want to make sure there's not some edge case somewhere where len(someObj) is not the same as someObj.<code>__len__</code>().</p>
