问我怎么才能把帆布带到前面呢？

EN

class window_tk():
def __init__(self,main):
    self.main=main
    self.canvas_org = tk.Canvas(self.main, bg='white')
    self.canvas_layer1 = tk.Canvas(self.main, bg='red')
    self.canvas_layer2 = tk.Canvas(self.main, bg='green')
    self.canvas_layer3 = tk.Canvas(self.main, bg='blue')
    self.canvas_layer4 = tk.Canvas(self.main, bg='black')
    self.btn_load = tk.Button(self.main,text = "Load Image",command = self.load_ct)
    self.btn_layer1 = tk.Button(self.main,text = "Draw in L1",command = self.bring_1)
    self.btn_layer2 = tk.Button(self.main,text = "Draw in L2",command = self.bring_2)
    self.btn_layer3 = tk.Button(self.main,text = "Draw in L3",command = self.bring_3)
    self.btn_layer4 = tk.Button(self.main,text = "Draw in L4",command = self.bring_4)

def bring_1(self):
    self.canvas_layer1.place(x=50,y=00)

def bring_2(self):
    self.canvas_layer2.place(x=50, y=00)

def bring_3(self):
    self.canvas_layer3.place(x=50, y=00)

def bring_4(self):
    self.canvas_layer4.place(x=50, y=00)