Python精灵模块的parallel_line平行线指令

import random
import turtle
from sprites import Screen,parallel_line    

def draw_line(p1,p2):
    turtle.penup();turtle.goto(p1);turtle.pd();turtle.goto(p2);turtle.penup()
    
screen = Screen()
screen.tracer(0,0)
screen.xy_grid()             # 显示坐标格子图

turtle.ht()
turtle.pensize(2)

A = (100,200)                # 一个定点
B = (0,0)                    # 一个定点 
draw_line(A,B)

C = (200,50)
D1,D2 = parallel_line([A,B],C)     # 返回线段AB的平行线段,默认长度为100
draw_line(D1,D2)              

turtle.done()