Probleme sur python

# -*- coding: utf-8 -*-

from tkinter import *

def initialisation():
    global photoL, imageL, personnage1,  photoH, imageH, personnage2, photoD,  imageD

    photoD = PhotoImage(file="MonDecor.gif")
    imageD = can1.create_image(406,305, image=photoD)
    photoH = PhotoImage(file="MonClou.gif")
    imageH = can1.create_image(50,50,anchor=CENTER, image=photoH)
    photoL = PhotoImage(file="MonTableau.gif")
    imageL = can1.create_image(60,50,anchor=CENTER, image=photoL)
    can1.pack()

    personnage1 = "Clou"
    personnage2 = "Tableau"

def depl_clou(x,y):
    print("depl_clou")
    can1.coords(imageH, x, y)


def config_clou():
    global personnage1
    print("config_clou")
    personnage1="Clou"

def clic(event):
    global personnage1
    print("clic")
    if personnage1 == "Clou":
        depl_clou(event.x, event.y)

def move():
    global x1, y1, dx, dy, flag
    print("move")

    if x1 > 210:
        x1, dx, dy = 210, 0, 15
    if y1 > 210:
        y1, dx, dy = 210, -15, 0
    if x1 < 10:
        x1, dx, dy = 10, 0, -15
    if y1 < 10:
        y1, dx, dy = 10, 15, 0

    x1, y1 = x1+dx, y1+dy
    can1.coords(imageL, x1, y1)
    if flag >0:
        print("flag>0")
        fen1.after(50,move)

def stop_it():
    global flag
    print("stop_it")
    flag=0

def start_it():
    global flag
    print("start_it")
    if flag == 0:
        flag=1
        move()

print("init")
x1, y1 = 10, 10
dx, dy = 15, 0
flag = 0

fen1 = Tk()
can1 = Canvas(fen1, bg='dark grey', height=610, width=812)
can1.pack(side=LEFT, padx=5, pady=5)
initialisation()

# oval1 = can1.create_image(20,50,anchor=CENTER,image=photoL)
bou1 = Button(fen1, text="Quitter", width=8, command=fen1.quit)
bou1.pack()
bou2 = Button(fen1, text="Démarrer", width=8, command=start_it)
bou2.pack()
bou3 = Button(fen1, text="Arrêter", width=8, command=stop_it)
bou3.pack()
can1.bind("<Button-1>", clic)


fen1.mainloop()