code: def docker(klass, container_id, shell, script, interval, deregister=None):
          
          ret = {
              'docker_container_id': container_id,
              'shell': shell,
              'script': script,
              'interval': interval
          }
          if deregister:
              ret['DeregisterCriticalServiceAfter'] = deregister
          return ret
docs: Invoke *script* packaged within a running docker container with
          *container_id* at a specified *interval* on the configured
          *shell* using the Docker Exec API.  Optional *register* after which a
          failing service will be automatically deregistered.