Import all bots and returns a bot class for the given label.
        Raise LookupError if no bot exists with this label.

def get_bot(self, bot_label):
        """
        Import all bots and returns a bot class for the given label.
        Raise LookupError if no bot exists with this label.
        """
        self.check_bots_ready()
        try:
            return self.bots[bot_label]
        except KeyError:
            message = "No installed bot with label '%s'." % bot_label
            for bot_cls in self.get_bots():
                if bot_cls.name == bot_label:
                    message += " Did you mean '%s'?" % bot_cls.label
                    break
            raise LookupError(message)