Python-сообщество

 from typing import Final, TypedDict
Square = int
EMPTY: Final = None
class Color(Enum):
    """Enum for piece colors."""
    RED = True
    BLUE = False
class PieceType(Enum):
    """Enum for piece types."""
    FLAG = 0
    MARSHAL = 1
class Piece:
    """A piece with type and color."""
    def __init__(self, type: PieceType, color: Color) -> None:
        self._type = type
        self._color = color
    @property
    def type(self) -> PieceType:
        """The type of the piece."""
        return self._type
    @property
    def color(self) -> Color:
        """The color of the piece."""
        return self._color
class Board:
    """A gameboard."""
    SIDE: Final = 10
    SIZE: Final = SIDE * SIDE
    def __init__(self) -> None:
        self._squares: list[Piece | None] = [EMPTY] * Board.SIZE
    def setup(self) -> None:
        # Исключительно для примера.
        self._squares[0] = Piece(PieceType.MARSHAL, Color.RED)
        self._squares[1] = Piece(PieceType.FLAG, Color.RED)
        self._squares[99] = Piece(PieceType.MARSHAL, Color.BLUE)
        self._squares[98] = Piece(PieceType.FLAG, Color.BLUE)
    def setup(self, square: Square) -> Color | None:
        if self._squares[square] is EMPTY:
            return None
        else:
            # А вот здесь Pylance ругается, что "color" is not a known member of "None"
            return self._squares[square].color