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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def listener_delete_event(self, listener_info):
 """Process listener delete event. This is lbaas v2 vif will be plugged into ovs when first listener is created and unpluged from ovs when last listener is deleted. as the data only contains listener id, we will scan all loadbalancers from db and delete the vdp if their admin state is down in that loadbalancer """

        lb_list = self.neutronclient.list_loadbalancers()
        for lb in lb_list.get('loadbalancers'):
            if not lb.get("listeners"):
                lb_id = lb.get('id')
                LOG.info("Deleting lb %s port" % lb_id)
                self.delete_lbaas_port(lb_id)