Summary
The second assignment reports that ROI_COLORS is not annotated with ClassVar. I think this is a false positive.
View in Playground: https://play.ruff.rs/d208fa8c-4554-415c-86cd-9986c0a0d76f
from typing import ClassVar
import matplotlib
class SomeClass:
ROI_COLORS: ClassVar[list] = matplotlib.color_sequences["tab20"]
# Shuffle the order around
ROI_COLORS = [*ROI_COLORS[0::2], *ROI_COLORS[1::2]] # Mutable class attributes should be annotated with `typing.ClassVar` (RUF012) [Ln 11, Col 18]
Version
ruff 0.14.4