Python class methods always execute twice

I am new to Python and ran into a problem when methods in a class Guialways execute twice.

Here is the gui class that inherits from Tkinter:

from Tkinter import *

class Gui (Tk):
    def createKdWindow(self):
        print("createKdWindow has been triggered")

    def activate(self):
        print ("activate has been triggered")
        self.tk.mainloop()

and here the method from ( init .py) is called :

from pm_test.gui import Gui

datgui = Gui()
datgui.createKdWindow()
datgui.activate()

When I run my program, I get the following console output:

createKdWindow has been triggered
activate has been triggered
createKdWindow has been triggered
activate has been triggered

So, my methods were executed twice. I do not know where this is from. Does anyone know how to solve this?

Fixed Entering code from init .py into a new module fixed this problem!