from math import hypot

class Vector:

def __init__(self, x=0, y=0):

self.x = x

self.y = y

def __repr__(self):

return "Vector({!r}, {!r})".format(self.x, self.y)

def __abs__(self):

return hypot(self.x, self.y)

def __bool__(self):

return bool(abs(self))

def __add__(self, other):

x = self.x + other.x

y = self.y + other.y

return Vector(x, y)

def __mult__(self, scalar):

return Vector(self.x * scalar, self.y * scalar)

def main():

v1 = Vector(2, 4)

v2 = Vector(2, 1)

print(v1)

print(v2)

# assert (v1 + v2) == Vector(4, 5)

# assert abs( * 3)

if __name__ == "__main__":

main()