def __str__(self):
        res = "---==  Plan ==---- \n"
        res += "name        : " + self.name + "\n"
        res += "version     : " + self.plan_version + "\n"
        for i in self.beliefs.list():
            res += "belief      : " + i + "\n"
        for i in self.desires.list():
            res += "desire      : " + i + "\n"
        for i in self.intentions.list():
            res += "intention   : " + i + "\n"