Bresenham's Line Algorithm code using python

Bresenham's Line Algorithm code using python language:

from PIL import Image as img

def PixelIn(x,y,im):
    im.putpixel((x,y),0)

def Br_Line(x1,y1, x2, y2):

    im = img.new(mode='1', size=(1000, 1000), color=1)
    x,y=x1,y1
    dx=x2-x1
    dy=y2-y1
    dt=2*(dy-dx)
    ds=2*dy
    d=2*dy-dx
    while x<x2:
        x+=1
        if d<0:
            d=d+ds
        else:
            y+=1
            d=d+dt

        PixelIn(x,y,im)
    im.save('Bresenhams Line Output.png')
    im.show()

if __name__=='__main__':
    Br_Line(100,500,700,700)