计时器未在Simpleguitk Python中启动

Question

我有以下代码。当我运行它时，所有内容都按预期运行，但计时器不起作用。我希望工程图的位置可以改变，但不会发生。

# Importing modules

import simpleguitk as sg
import random as rd

# Define global variables
message = "Python is Fun!"
position = [50, 50]
width = 500
height = 500
interval = 2000


# Event handlers

# Handler for message displayed
def new_text(text):
    """Change message displayed"""
    global message
    message = text


# handler for timer
def tick():
    """Change the posotion"""
    global width, height, position
    x = rd.randrange(0, width)
    y = rd.randrange(0, height)
    position[0] = x
    position[1] = y


# handler to draw canvas
def draw(canvas):
    global message, position
    canvas.draw_text(message, position, 16, "purple")


# Create Frame
frame = sg.create_frame("Main Window", width, height)

# Register event handlers
frame.set_draw_handler(draw)
frame.add_input("Enter Message", new_text, 150)

# Set timer
timer = sg.create_timer(interval, tick)

# start frame animation
frame.start()
timer.start()

我的代码有什么问题？请帮助。谢谢。