Python - Tkinter - Change Pages

#
# https://www.reddit.com/r/learnpython/comments/4x2q73/python_35_tkinter_key_bindings_for_a_specific/
#

from tkinter import *
from tkinter import filedialog
from tkinter.ttk import *
from PIL import Image, ImageTk
import numpy as np


class App(Tk):

    def __init__(self, *args, **kwargs):

        Tk.__init__(self, *args, **kwargs)

        Tk.wm_title(self, "GUI V0.5")


        container = Frame(self)
        container.winfo_toplevel().geometry("600x600")
        container.pack(side="top", fill="both", expand=True)
        container.grid_rowconfigure(0, weight=1)
        container.grid_columnconfigure(0, weight=1)


        self.frames = {}

        for F in (tagPage, heatPage):
            name = F.__name__

            frame = F(container, self)

            self.frames[name] = frame

            frame.grid(row=0, column=0, sticky="nsew")

        self.show_frame('tagPage')

    def show_frame(self, cont):

        frame = self.frames[cont]
        frame.tkraise()
        frame.focus_set()


class heatPage(Frame):

    def __init__(self, parent, controller):
        Frame.__init__(self, parent)
        self.controller = controller

        self.initUI()

    def initUI(self):

        self.button = Button(self, text="Change", command=lambda:self.controller.show_frame("tagPage"))
        self.button.pack()

        self.posNegDisp = Label(self, text="heatPage:")
        self.posNegDisp.pack()

        self.bind('1', self._set_feature_Val)
        self.bind('2', self._set_feature_Val)


    def _set_feature_Val(self, event):

        if event.char == '1':
           self.featureLabel = 1
           self.posNegDisp.config(text = "heatPage:\n     Positive")
           print("heatPage: positive")
        elif event.char == '2':
           self.featureLabel = -1
           self.posNegDisp.config(text = "heatPage:\n     Negative")
           print("heatPage: negative")


class tagPage(Frame):

    def __init__(self, parent, controller):
        Frame.__init__(self, parent)
        self.parent = parent
        self.controller = controller

        self.initUI()

    def initUI(self):

        self.button = Button(self, text="Change", command=lambda:self.controller.show_frame("heatPage"))
        self.button.pack()

        self.posNegDisp = Label(self, text="tagPage:")
        self.posNegDisp.pack()

        self.bind('1', self._set_feature_Val)
        self.bind('2', self._set_feature_Val)

    def _set_feature_Val(self, event):

        if event.char == '1':
           self.featureLabel = 1
           self.posNegDisp.config(text = "tagPage:\n     Positive")
           print("tagPage: positive")
        elif event.char == '2':
           self.featureLabel = -1
           self.posNegDisp.config(text = "tagPage:\n     Negative")
           print("tagPage: negative")

app = App()
app.mainloop()