def user_login(window):
    # some code to find whether valid or not. Valid: found = True
    entry_value = entry_value.get()
    if found:
        messagebox.showinfo(title='Successful login',
                            message='Valid password. Welcome to 7vinBB air traffic control system !')
    else:
        messagebox.showerror(title='Error',
                             message='Invalid password. Please enter again. You have  ' + str(5-count1) + ' times left')

class LoginFrame(Frame):
    def __init__(self, master):
         super().__init__(master)
         self.entry_value = entry(self,
                                  font='Courier 17')
         self.login_button = button(command=lambda: user_login(root))

         self.entry_value.place(x=330, y=245)
         self.login_button.place(x=440, y=420)

 root = Tk()
 lf = LoginFrame(root)
 root.mainloop()