(python tkinter)带有类的页面，变量传递到其他页面，不能用作标签: PY_VAR0

import tkinter as tk

class MyPage(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        self.parent = parent

class MyPage(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        self.parent = parent
        self.my_variable = tk.StringVar()

    def pass_variable(self):
        other_page = OtherPage(self.parent)
        other_page.set_variable(self.my_variable.get())
        self.parent.show_page(other_page)

class OtherPage(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        self.parent = parent
        self.variable_label = tk.Label(self, text="")

    def set_variable(self, variable):
        self.variable_label.config(text=variable)

class MyApp(tk.Tk):
    def __init__(self):
        tk.Tk.__init__(self)
        self.pages = {}
        self.current_page = None

    def add_page(self, page):
        self.pages[type(page).__name__] = page

    def show_page(self, page):
        if self.current_page:
            self.current_page.pack_forget()
        self.current_page = page
        self.current_page.pack()

if __name__ == "__main__":
    app = MyApp()
    my_page = MyPage(app)
    app.add_page(my_page)
    app.show_page(my_page)
    app.mainloop()