nircmd with python 3.x

import subprocess
import tkinter

class JanelaPrincipal(tkinter.Tk):
    def __init__(self):
        tkinter.Tk.__init__(self)
        self.title("Fala autônoma")
        self.minsize(370, 150)
        self.resizable(False, False)
        frame_x = tkinter.Frame()
        frame_z = tkinter.Frame()
        frame_x.grid(row=0, column=0)
        frame_z.grid(row=0, column=1)
        tkinter.Label(frame_x, text="O que você deseja que eu fale? Insira aí embaixo!", font=('Arial', 10, 'bold'))\
            .grid(row=1, column=0)
        self.texto = tkinter.Text(frame_x, height=7, width=int(370//8.3), relief='groove')
        self.texto.grid(row=2, column=0, padx=2)
        bt = tkinter.Button(frame_z, text="Falar", command=self.fala).grid(row=0, column=1, padx=5)
        self.mainloop()

    def fala(self):
        subprocess.call("nircmd speak text \"%s\"" % self.texto.get(1., tkinter.END))

JanelaPrincipal()