This is a great guide. Awhile back, I wrote a blog post[1], "Python double-under, double-wonder," trying to dispel one common misconception I find among new Pyt

This is a great guide. Awhile back, I wrote a blog post[1], "Python double-under, double-wonder," trying to dispel one common misconception I find among new Python programmers. That is, they often think that these methods are "magical" and thus shouldn't be implemented in their own classes (by "mere mortals"). That is true for a small subset of dunder methods (e.g. `__new__`), but not true for many of them (e.g. `__init__`, `__iter__`, `__call__`, `__len__`). A better way to think about it is that the double-underscore naming convention simply means "reserved by the core Python team" -- they offer ways to hook into widely-implemented protocols in the Python runtime. That also means you should never invent your own dunder methods or dunder attributes. This is another mistake new Python programmers -- and even some experienced Python programmers, even some Python framework writers! -- tend to make, "imitating" this naming convention to mark parts of their own code as "magic." Don't do that: the whole idea is that the core Python team reserved this namespace (`__*__`) for Python-wide protocols. [1]: https://amontalenti.com/2013/04/11/python-double-under-double-wonder https://amontalenti.com/2013/04/11/python-double-under-doubl...