import math


def line_intersection(line1, line2):
    xdiff = (line1[0][0] - line1[1][0], line2[0][0] - line2[1][0])
    ydiff = (line1[0][1] - line1[1][1], line2[0][1] - line2[1][1])

    def det(a, b):
        return a[0] * b[1] - a[1] * b[0]

    div = det(xdiff, ydiff)
    if div == 0:
        raise Exception('lines do not intersect')

    d = (det(*line1), det(*line2))
    x = det(d, xdiff) / div
    y = det(d, ydiff) / div
    return x, y


def norm(point1, point2):
    xdiff = point1[0] - point2[0]
    ydiff = point1[1] - point2[1]

    norm = math.sqrt(xdiff * xdiff + ydiff * ydiff)
    # print norm
    return norm


def str_tuple(str: str):
    val = eval(str)
    return val