AttributeError: 'RadosPool' object has no attribute 'commit'

I setup the gwcli following http://docs.ceph.com/docs/master/rbd/iscsi-target-cli/
And when I executed "gwcli ls" command on top dir, this issue happened, is this a bug?

[root@gw1 iscsi]# gwcli ls
'RadosPool' object has no attribute 'commit'

[root@gw1 iscsi]# gwcli ls iscsi-target
o- iscsi-target .......................................................................... [Targets: 1]
o- iqn.2017-11.test.com:tgt1 ....................................................... [Gateways: 1]
o- gateways ................................................................. [Up: 1/1, Portals: 1]
| o- gw1 ....................................................................... [10.16.0.198 (UP)]
o- host-groups ....................................................................... [Groups : 0]
o- hosts ............................................................................... [Hosts: 0]