Need help trying to test function to find area of rectangle using co-ordinates

I have a Rectangle class that finds the area of a Rectangle using top-left and bottom-right coordinates. I'm having trouble writing up a test function to test the code and verify it works.

class Rectangle: # rectangle class
    # make rectangle using top left and bottom right coordinates
    def __init__(self,tl,br):
        self.tl=tl
        self.br=br
        self.width=abs(tl.x-br.x)  # width
        self.height=abs(tl.y-br.y) # height
    def area(self):
        return self.width*self.height

So far I have written this which leads to an AttributeError: 'tuple' object has no attribute 'x'

def test_rectangle():
    print("Testing rectangle class")
    rect = Rectangle((3,10),(4,8))
    actual = rect.area()
    print("Result is %d" % actual)

What can I change to the code in order to make it work?