解决python彩色螺旋线绘制引发的问题

import turtle
import time
turtle.pensize(2)
turtle.bgcolor('black')
colors = ['red', 'yellow', 'purple', 'blue']
turtle.tracer(False)
for x in range(400):
 turtle.forward(2*x)
 turtle.color(colors[x % 4])
 turtle.left(91)
turtle.tracer(True)
time.sleep(3) 

from turtle import *
from time import *
p = Turtle()
p.pensize(2)
p.bgcolor("black")
colors = ["red", "yellow", 'purple', 'blue']
p._tracer(False)
for x in range(400):
 p.forward(2*x)
 p.color(colors[x % 4])
 p.left(91)
p._tracer(True)

from turtle import *
from time import *
import turtle
p = Turtle()
p.pensize(2)
turtle.bgcolor("black")
colors = ["red", "yellow", 'purple', 'blue']
p._tracer(False)
for x in range(400):
 p.forward(2*x)
 p.color(colors[x % 4])
 p.left(91)
p._tracer(True)

turtle.done()

turtle.bgcolor("black")