Python 3.x 创建默认值

我有一个点类，它有2-d点实例。我还有一个震级函数，里面返回所说点的震级。下面是我的代码

class Point:
#    """2-D Point objects."""

    def __init__(self, x, y):
    #       """Initialize the Point instance"""
        self.x = x
        self.y = y

    def get_magnitude(self):
    #       """Return the magnitude of vector from (0,0) to self."""
        return math.sqrt(self.x ** 2 + self.y ** 2)

    def __str__(self):
        return 'Point at ({}, {})'.format(self.x,self.y)

    def __repr__(self):
        return "Point(x={},y={})".format(self.x,self.y)
point = Point(x=3, y=4)
print(str(point))
print(repr(point))
print(point)

…完成所有这些之后，最后一部分是实现默认点0,0。有什么建议吗？它应该是这样工作的

    point2 = Point()
    print(point2)
Point(x=0, y=0)
    point3 = Point(y=9)
    print(point3)
Point(x=0, y=9)

您可以传递给初始值设定项，就像传递给任何其他函数一样

def __init__(self, x=0, y=0):
#       """Initialize the Point instance"""
    self.x = x
    self.y = y