如何在tkinter中为class创建多个标签

from tkinter import Tk, Label, Frame

root = Tk()

class MyFrame(Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.initUI()

def initUI(self):
    label1 = Label(self, text="标签1")
    label1.pack()

    label2 = Label(self, text="标签2")
    label2.pack()

    label3 = Label(self, text="标签3")
    label3.pack()

frame = MyFrame(root)
frame.pack()

root.mainloop()