dunder: Double under (Underscore) – magic methods #

dir() to see the dunder methods

Python docs: datamodel

3.3 special method names #

• __new__ create a new instance
• __init__ created 之后初始化
• __del__
• __str__, __repr__ : object representation
• __bytes__
• __format__
• __getitem__, __setitem__, __len__: iteration, [] (indexer operator)
• __call__: object invocation
• __lt__, __le__, __eq__, __ne__, __gt__, __ge__
• __hash__
• __bool__

3.4 customizing attribute access #

• __getattr__
• __getattribute__
• __setattr__
• __delattr__
• __dir__

3.3.2.1 Customizing module attribute access #

3.3.2.2 implementing descriptors

3.3.2.3 invoking descriptors

3.3.2.4 __slots__

3.3.3 customizing class creation

3.3.3.1 metaclass

3.3.3.2 resolving MRO entries

3.4 coroutines

awaitable object: 实现了 __await__

coroutine objects returned from async def functions are awaitable