SystemFailoverBindingStub.get_peer_address is returning blank strings

I have setup BIGIP 11.4 HA configuration. I have two nodes. My requirement is to list al nodes present in HA. When I am using get_peer_address method of SystemFailoverBindingStub it is returning blank strings.

 

I am referring link to get this informarion.

 

Anyone facing this problem? Any pointers?