import tkinter as tk
import tkinter.ttk as ttk

class Controller(object):
    def __init__(self, app):
        self.app = app

    def run_process(self):
        print("Run")
        return 0

class Application(tk.Tk):
    def __init__(self):
        super().__init__()
        self.con = Controller(self)
        self.create_control_variables()
        self.create_widgets()

    def create_control_variables(self):
        pass

    def create_widgets(self):
        self.b = ttk.Button(master=self, text="Start", command=self.con.run_process)
        self.b.grid(row=1, column=0)


# --------------------------
# Execution
# --------------------------
if __name__ == "__main__":
    app = Application()
    app.mainloop()