[Python] Overiding __mul__ in two dimensional vector class to preserve commutivity

I have defined the following class:

class Point(object):

def __repr__(self):
return "("+str(self.x)+","+str(self.y)+")"

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

def __add__(self, point):
return Point(self.x+point.x,self.y+point.y)

def __sub__(self, point):
return Point(self.x-point.x,self.y-point.y)

def __mul__(self, num):
return Point(num*self.x,num*self.y)

def length(self):
return (self.x**2 + self.y**2)**.5


And the following code works:

x = Point(1,2)
y = Point(1,3)
print x+y
print (y+x)
print (x-y)
print (y-x)
print y*3


with output:

(2,5)
(2,5)
(0,-1)
(0,1)
(3,9)


But this does not:

print 3*y


It gives the following error:

----> 1 print 3*y
TypeError: unsupported operand type(s) for *: 'int' and 'Point'


Which is because the point class is being fed into the int mul function, I'm assuming. How can I keep the definition of point contained in the Point class and still have 3*y return the same as y*3?

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