Is it a idiomatic to implicitly make a class convertible to bool?
<p>For some reason a lot of types are implicitly convertible to boolean values, despite Python's "be explicit" guideline. Anyway...</p>

<p>Is it idiomatic to make custom classes also implicitly convertible to bool, where appropriate? If yes, what function should I (re)define? In my specific case, I have an <code>Image</code> class; I want to make it convertible to bool such that it is <code>True</code> when it is holds data loaded from somewhere (a file), and <code>False</code> otherwise.</p>
