tkinter - code in two files

### main.py ###

import tkinter
from calc import calc_from_calc

mainWindow = tkinter.Tk()

entry1 = tkinter.Entry(mainWindow)
entry1.grid(row=0, column=1)

entry2 = tkinter.Entry(mainWindow)
entry2.grid(row=1, column=1)

buttonCalc = tkinter.Button(mainWindow, text="Calculate", command=lambda:calc_from_calc(entry1, entry2, labelResult))
buttonCalc.grid(row=3, column=1)

labelResult = tkinter.Label(mainWindow, text='Result is:')
labelResult.grid(row=4, column=1)

mainWindow.mainloop()


### calc.py ###

def calc_from_calc(arg1, arg2, arg3):
    result = int(arg1.get()) + int(arg2.get())
    print(result)
    arg3.configure(text="Result is:{}".format(result))