def show_message(self, message, template_path='./data/display_message.html'):
    """Shows a text message in full screen.

    Args:
      message: text to show.
      template_path: a html template to use. It should contain "{{ message }}".
    """
    self._generate_page(
        template_path=template_path, kwargs={
            'message': message
        })
    self._relaunch()