code: def get_fw_rule(self, rule_id):
          
          rule = None
          try:
              rule = self.neutronclient.show_firewall_rule(rule_id)
          except Exception as exc:
              LOG.error("Failed to get firewall rule for id %(id)s "
                        "Exc %(exc)s", {'id': rule_id, 'exc': str(exc)})
          return rule
docs: Return the firewall rule, given its ID.