Just take any large python project and search the bug trackker for : &quot;AttributeError: &#x27;NoneType&#x27; object has no attribute ...&quot;<p>You&#x27;ll find plenty of those. So people are wasting time tracking and fixing something that could have been found by a machine (a compiler in this case) in microseconds. A colleague of mine once stated: &quot;unit tests are a poor man&#x27;s compiler&quot;.