i am trying to use the openstackclient (https://docs.openstack.org/newton/user-guide/common/cli-install-openstack-command-line-clients.html), but it seems than I cannot use it to see cinder volume snapshot, even the doc say it is possible 

(https://docs.openstack.org/python-openstackclient/latest/cli/decoder.html#cinder-cli) 

it says 

"

(my-virt-env) user@ostack:~$ openstack snapshot list
openstack: 'snapshot list' is not an openstack command. See 'openstack --help'.
Did you mean one of these?
  endpoint add project
  endpoint create
  endpoint delete
  endpoint group add project
  endpoint group create

...

"

what am i missing?

thank you.