def test_build_event(self):
        evt = event.build_event("evt_name", arg1="val1", arg2=None)
        assert evt.name == "evt_name"
        assert evt.args == {'arg1': "val1", 'arg2': None}
def getR(self):
        # x 分量與 y 分量
        x = self.p1.x - self.p2.x
        y = self.p1.y - self.p2.y
        return math.sqrt(x * x + y * y)