Thanks Miguel Brito !

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!