from random import randint, random

def randomLine(length=None):
    if not length or length < 2:
        length = randint(2,10)
    line = []
    for i in range(length):
        line.append([round(random() * 1000, 2), round(random() * 1000, 2)])
    return line

def lineLength(line=None):
    if not line:
        line = randomLine()
    if len(line) < 2:
        return None
    length = 0
    for i in range(len(line) - 1):
        length += ((line[i][0] - line[i+1][0]) ** 2 + (line[i][1] - line[i+1][1]) ** 2) ** 0.5
    return length