Python Tkinter Check if Frame exists

Question

I am trying to do the following:

1. Create a Tkinter App with a 'File' menu.
2. The File Menu has 2 options, Add and View.
3. The Add option adds a Frame and then adds a Label widget (Label 1) in the frame.
4. If I then select the View option form the file menu, it should print out whether or not a Frame widget already exists.

Following is my attempt at it, but I receive the error

AttributeError: 'Test' object has no attribute 'tk'

when I select the View option, can someone please help point out what I am missing here?

from tkinter import Tk, Menu, Label, Frame
class Test():
    def __init__(self):
        self.gui = Tk()
        self.gui.geometry("600x400")

        menu = Menu(self.gui)
        new_item1 = Menu(menu)
        menu.add_cascade(label='File', menu=new_item1)
        new_item1.add_command(label='Add', command=self.addlbl)
        new_item1.add_command(label='View', command=self.viewlbl)    

        self.gui.config(menu=menu)
        self.gui.mainloop()

    def addlbl(self):
        f=Frame()
        f.pack()
        lbl1 = Label(f, text="Label 1").grid(row=0, column=0)

    def viewlbl(self):
        print(Frame.winfo_exists(self))      

T=Test() 

Answer 1

I replicated your problem. I got the code below to work using Python3.4 on Linux. f needs to become self.f. I named it self.frame. This enables the frame to be accessed outside of the method it is created in.

from tkinter import Tk, Menu, Label, Frame
class Test():

def __init__(self):
    self.gui = Tk()
    self.gui.geometry("600x400")
    menu = Menu(self.gui)
    new_item1 = Menu(menu)
    menu.add_cascade(label='File', menu=new_item1)
    new_item1.add_command(label='Add', command=self.addlbl)
    new_item1.add_command(label='View', command=self.viewlbl)    
    self.gui.config(menu=menu)
    self.gui.mainloop()

def addlbl(self):
    self.frame = Frame(self.gui)
    self.frame.pack()
    lbl1 = Label(self.frame, text="Label 1")
    lbl1.grid(row=0, column=0)

def viewlbl(self):
    print('frame exists {}'.format(self.frame.winfo_exists()))


T=Test()