code: public ServerFilter powerStates(PowerState... states) {
          allItemsNotNull(states, "Power states");
  
          predicate = predicate.and(combine(
              s -> s.getDetails().getPowerState(), in(map(states, PowerState::getCode))
          ));
  
          return this;
      }
docs: Method allow to find servers with specified power state of target servers
  
  @param states is a list target server power states
  @return {@link GroupFilter}