pytest/plib/base.py

class PointError(Exception):
    pass


class Point:
    def __init__(self, x: int, y: int) -> None:
        if not isinstance(x, int) or not isinstance(y, int):
            raise PointError("x,y should be an integer type")
        self.x = x
        self.y = y

    def __add__(self, other: "Point") -> "Point":
        return Point(self.x + other.x, self.y + other.y)

    def __sub__(self, other: "Point") -> "Point":
        return Point(self.x - other.x, self.y - other.y)

    def __eq__(self, other: object) -> bool:
        if not isinstance(other, Point):
            raise NotImplementedError
        return self.x == other.x and self.y == other.y

    def distance_to(self, other: "Point") -> float:
        p = self - other
        return (p.x ** 2 + p.y ** 2) ** 0.5