b.pack(side='top')

def new_window(self):
    self.count += 1
id = 'New window #%s' % self.count
window = tk.Toplevel(self)
label = tk.Label(window, text=id)
label.pack(side='top', fill='both', padx=10, pady=10)
if __name__ == '__main__':
    root = tk.Tk()
view = View(root)
view.pack(side='top', fill='both', expand=True)
root.mainloop()
Python 3 и tkinter открывают новое окно, нажав кнопку