tkinter template with an App class.

tk_template_02.py

import tkinter as tk
from tkinter import ttk

class App(tk.Tk):
  def __init__(self):
    super().__init__()
    self.geometry("600x400+500+10")
    self.title("App")
    self.style = ttk.Style()
    self.style.theme_use("clam")

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