Summary

The Python metaclass system is something every Python programmer uses all the time, perhaps without even knowing about it. Every class should be created through some (subclass of) type, which allows for endless customization and magic. Instead of statically defining your class, you can now have it created as you normally would and dynamically add, modify, or remove attributes from your class during definition; very magical but very useful. The magic component, however, is also the reason it should be used with a lot of caution. While metaclasses can be used to make your life much easier, they are also amongst the easiest ways of producing completely incomprehensible code.

Regardless, there are some great use-cases for metaclasses and many libraries such as SQLAlchemy and Django use metaclasses to make your code work much easier and arguably better. Actually comprehending the magic that is used inside is generally not needed for the usage of these libraries, which makes the cases defendable...