title: Kivy: Set label text then change it after a second
body: <p>I have made a coin flip button that shows the result in Label, every time the button is pressed, the result change according to the function. </p>
  
  <pre><code>def coin_flip(self):
      sound_1 = SoundLoader.load('coin.wav')
      res = random.randint(1,2)
      if sound_1:
          sound_1.play()
      if res == 1:
          self.coin_f_result.text = "HEAD"
      else:
          self.coin_f_result.text = "TAIL"
  </code></pre>
  
  <p>What I want to do is, showing the result in the Label, and then, after a second set the Label text as " ". Here's what I tried, but i only get the function calling delayed, and the label text is set directly to " ".</p>
  
  <pre><code>def coin_flip(self):
      sound_1 = SoundLoader.load('dice.wav')
      res = random.randint(1,2)
      if sound_1:
          sound_1.play()
      if res == 1:
          self.coin_f_result.text = "HEAD"
          time.sleep(1)
          self.coin_f_result.text = " "
      else:
          self.coin_f_result.text = "TAIL"
          time.sleep(1)
          self.coin_f_result.text = " "
  </code></pre>