title: Could not load icon plyer library
body: <p>I have a little problem with Plyer library, I'm trying to custom a notification's appereance but evrything is okay until I try to replace the default icon of the notification, here's my code:</p>
  <pre><code>from plyer import notification
  notification.notify(title='Managen', message='Notification',app_icon = r'C:\Users\Santiago\Pictures\icon.ico',timeout = 10)
  </code></pre>
  <p>This is the output:</p>
  <pre><code>Exception in thread Thread-1:
  Traceback (most recent call last):
    File &quot;C:\Users\Santiago\AppData\Local\Programs\Python\Python38-32\lib\threading.py&quot;, line 932, in _bootstrap_inner
      self.run()
    File &quot;C:\Users\Santiago\AppData\Local\Programs\Python\Python38-32\lib\threading.py&quot;, line 870, in run
      self._target(*self._args, **self._kwargs)
    File &quot;C:\Users\Santiago\AppData\Local\Programs\Python\Python38-32\lib\site-packages\plyer\platforms\win\libs\balloontip.py&quot;, line 208, in balloon_tip
      WindowsBalloonTip(**kwargs)
    File &quot;C:\Users\Santiago\AppData\Local\Programs\Python\Python38-32\lib\site-packages\plyer\platforms\win\libs\balloontip.py&quot;, line 132, in __init__
      raise Exception('Could not load icon {}'.format(app_icon))
  Exception: Could not load icon C:\Users\Santiago\Pictures\icon.ico
  </code></pre>
  <p>I don't know what is exactly happening, if you could help me it'd be great, beforehand thanks.</p>