Hi, could you tell me why I got error for optional attribute?
>>> from dataclasses import dataclass
>>> from typing import Optional
>>> @dataclass
... class Color:
... r: float
... g: float
... b: float
... alpha: Optional[float]
...
>>> blue = Color(r=0, g=0, b=255)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: __init__() missing 1 required positional argument: 'alpha'
Thansk in advance!