Python学习开始遇到AttributeError问题

学习python,明明代码和书上一样,但是就是报错

import turtle
t = turtle.pen()
turtle.bgcolor("black")
colors = ["red","yellow","blue","green","orange","purple","white","gray"]
sides = int(turtle.numinput("Number of sides","How many sides do you want(1-8)?",4,1,8))
for x in range(360):
    t.pencolor(colors[x % sides]) #
    t.forward(x * 3 / sides + x)  
    t.left(360 / sides + 1)     
    t.width(x * sides / 200)     

报错:AttributeError: 'dict' object has no attribute 'pencolor'
但是我在其他程序中,也用到pencolor这个属性,又是正常的

两个解决方法:
一、把第二行改成: t = turtle.Turtle() 即可
或者:
二、第二行删除,7~10行的 t. 改成 turtle.