>>> import math
>>> from Tkinter import *
>>> import time
>>> class Point: ##Class Point is defined so that point may be used
    def __init__(self, x=0.0, y=0.0):
        self.x = x
        self.y = y
    def calDis(self,p):
        return math.sqrt((p.x-self.x)**2+(p.y-self.y)**2)


>>> class Polyline:
    def __init__(self, points = []):
        self.points = points
    def getLength(self):
        length = 0.0
        for i in range(len(self.points)-1):
            length += math.sqrt((self.points[i].x-self.points[i+1].x)**2+(self.points[i].y-self.points[i+1].y)**2)
            if length > 200: ##To create the red square
                root = Tk()
                can = Canvas(root, width = 600, height = 600)
                can.pack()
                can.create_rectangle(200,166,400,332, fill="red")
                can.create_text(300,249, text=" Polyline Length\n is more than 200")
                for x in range(0,400):
                                        can.move(1,5,0)
                                        can.move(2,5,0)
                                        root.update()
                                        time.sleep(0.02)
                                root.mainloop()
                return length
            if length < 200: ##To create the blue square
                root = Tk()
                can = Canvas(root, width = 600, height = 600)
                can.pack()
                can.create_rectangle(200,166,400,332, fill="blue")
                can.create_text(300,249, text=" Polyline Length\n is less than 200")
                root.mainloop()
                return length


>>> p1 = Point(789,654)
>>> p2 = Point(564,574)
>>> pointList = [p1,p2]
>>> polyline = Polyline(pointList)
>>> print polyline.getLength()