How to add a CT action in the switch's flow table?

[TheMasterOfMagic]

I'm a new beginner learning ovs and ryu and I encountered a problem, which I still cannot solve after searching the official documents.

As far as I know, for example, to tell the switch to hand in any incoming ARP flows to the controller, I can do the below thing in python:

match = parser.OFPMatch(eth_type=ether_types.ETH_TYPE_ARP)
actions = [
    parser.OFPActionOutput(ofproto.OFPP_CONTROLLER, ofproto.OFPCML_NO_BUFFER)
]
self.add_flow(datapath, 1, match, actions)

which are equivalent to the followings ovs-ofctl command.

ovs-ofctl add-flow <bridge> "priority=1,arp,actions=CONTROLLER:65535"

And my question is, how to tell the switch to do the specified CT action? or what are equivalent to the command below?

ovs-ofctl add-flow <bridge> "ip,nw_dst=10.0.0.1,actions=ct(commit,table=1,nat(dst=10.0.0.2))"

PS:

• After seach the source code, I've found the parser.NXActionCT and parser.NXActionNAT class and the example usage, which didn't work.

If there is any info that may help but not posted here, please feel free to let me know!