some behaviour that needs to be implemented -> dunder methods, double underscore methods

data model methods

top-level function or top-level syntax --> corresponding __ functions

python data model is a means by which you can implement protocols. Those protocols have some abstract meaning depending on the object itself. 用户可以使用Python Data Model来实现协议. 这些协议

One top-level syntax parentheses that coming after the name of an object is call protocol.

Python meta class Three common features： generators, decorators, and context manager

Python runs code from top to bottom linearly.

Python dis stands for disassemble. We can use it to disassemble and see what actually happens in Python byte code.

executable runtime runs at runtime