# From: https://www.pythontutorial.net/tkinter/tkinter-object-oriented-window/

import tkinter as tk
from tkinter import ttk
from tkinter.messagebox import showinfo

class App(tk.Tk):
    def __init__(self):
        super().__init__()

        self.title('test')
        self.geometry('300x50')
        self.resizable(0,0)
        self.columnconfigure(0, weight=1)
        self.columnconfigure(1, weight=1)
        self.columnconfigure(2, weight=1)
        self.columnconfigure(3, weight=1)

        self.label = ttk.Label(self, text='testing label')
        self.label.grid(column=1, row=0, columnspan=2, sticky='nsew')

        self.button = ttk.Button(self, text='testing button')
        self.button['command'] = self.button_clicked
        self.button.grid(column=1, row=1, columnspan=2, sticky='nsew')

    def button_clicked(self):
        showinfo(title='Information', message='testing button method')

if __name__ == "__main__":
    app = App()
    app.mainloop()