In Praise of Metaclasses!

Much maligned and misunderstood, metaclasses might be one of Python’s most useful features. On the surface, it might not be clear why this would be the case. Just the name “metaclass” alone is enough to conjure up an image of swooping manta rays and stinging bats attacking your coworkers in a code review. I’m sure that there are also some downsides, but metaclasses really are a pretty useful thing to know about for all sorts of problems of practical interest to systems programmers. This includes simplifying the specification of network protocols, parsers, and more. In this installment, we’ll explore the practical side of metaclasses and making Python do some things you never thought possible. Note: This article assumes the use of Python 3.