Shows system notification message according to system requirements.

            `message`
                Status message.

def _notify(self, task, message):
        """ Shows system notification message according to system requirements.

            `message`
                Status message.
            """

        if self.notify_func:
            message = common.to_utf8(message.strip())
            title = common.to_utf8(u'Focus ({0})'.format(task.name))
            self.notify_func(title, message)