New note by clacke

Single question mark thing: If you type a question mark after a Python object, it shows you annotations and documentation related to that object:

In [1]: from dataclasses import dataclass
In [2]: @dataclass
   ...: class Asdf:
   ...:     """This thing does stuff.
   ...:
   ...:     It can foo and bar.
   ...:     """
   ...:
   ...:     qwer: int
   ...:     zxcv: str
   ...:
In [3]: Asdf?
Init signature: Asdf(qwer: int, zxcv: str) -> None
Docstring:
This thing does stuff.

It can foo and bar.
Type:           type
Subclasses:

Cool stuff. Very useful. Very helpful. Don't leave home without it.