Python:如何在函数外部使用函数中定义的图形？

import turtle

def draw_square():
    square = turtle.Turtle()
    for _ in range(4):
        square.forward(100)
        square.right(90)
    return square

my_square = draw_square()
my_square.color("red")
my_square.penup()
my_square.goto(100, 100)
my_square.pendown()
my_square.circle(50)

turtle.done()

import turtle

my_square = None

def draw_square():
    global my_square
    my_square = turtle.Turtle()
    for _ in range(4):
        my_square.forward(100)
        my_square.right(90)

draw_square()
my_square.color("red")
my_square.penup()
my_square.goto(100, 100)
my_square.pendown()
my_square.circle(50)

turtle.done()

import turtle

class Square:
    def __init__(self):
        self.square = turtle.Turtle()
        for _ in range(4):
            self.square.forward(100)
            self.square.right(90)

my_square = Square()
my_square.square.color("red")
my_square.square.penup()
my_square.square.goto(100, 100)
my_square.square.pendown()
my_square.square.circle(50)

turtle.done()