trouble with tkinter, with source

[walter hanagriff]

this is just a framework i am using as a simplified test case for adding
tkinter to my main program
The first class makes the first frame of the program giving the user 3
options, whichever option he chooses opens up a second frame from the
second class, but they just keep piling up, i want it so that if an
options frame is there when they
pick another frame, the first options frame will disappear
i can easily delete the main frame from the Main class, but dont know
how to call the frames from the defs in the second class, whether i try
to call them from Main or Step2, so how do i make what i want happen
i think that best explains what i want, any help would be appreciated

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class Main:
    # this function makes the first frame for the program
    def __init__(self):
        frame = Frame(root, width = 300, height = 400)
        frame.pack()
        Label(frame, text = "this program figures the area, perimeter,
and power of n \n"
        "____________________________________________").pack()

        self.v = IntVar()
        self.v.set("1")
        Radiobutton(frame, text = "1 = Find the power of a number",
variable = self.v, value = 1).pack(anchor = W)
        Radiobutton(frame, text = "2 = Find the area of a shape",
variable = self.v, value = 2).pack(anchor = W)
        Radiobutton(frame, text = "3 = Find the perimeter of a shape",
variable = self.v, value = 3).pack(anchor = W)

        next = Button(frame, text = "Next", padx = 10, command =
self.ifpick)
        next.pack(side = LEFT, padx = 5)
        close = Button(frame, text = "Close", padx = 10, command =
root.destroy)
        close.pack(side = LEFT, padx = 5)

    # this says which frame to open depending on which radiobutton above
is picked by user
    def ifpick(self):
        st = Step2()
        if self.v.get() == 2 or 3:  st.frame2.frame22.destroy
        if self.v.get() == 1:  st.frame2()
        if self.v.get() == 2:  st.frame3()
        if self.v.get() == 3:  st.frame4()

# Destroys frames not needed then displays all but the first frame in
the program
class Step2:
    # this frame is for the power of a number, radiobutton option v == 1

    def frame2(self):
        frame22 = Frame(root, width = 300, height = 410)
        frame22.pack()
        Label(frame22, text = "this frame is where you put information
to get power of n \n"
        "______________________________________________").pack()

    # this frame is for the perimeter of a shape, radiobutton option v
== 3
    def frame4(self):
        frame44 = Frame(root, width = 300, height = 400)
        frame44.pack()
        Label(frame44, text = "this frame is where you put information
to get the perimeter of a shape \n"
        "______________________________________________").pack()

if __name__== '__main__':
    root = Tk()
    root.title(title)
    start = Main()
    root.mainloop()