docs: private List<ENTITY> getByComplexKeys(Collection<KEY> ids) {
          List<ENTITY> entities = new ArrayList<ENTITY>(ids.size());
          for (KEY key : ids) {
              List<Match> matches = queryGenerator.getKeyMatches(key);
              entities.addAll(find(matches.toArray(new Match[matches.size()])));
  
          }
          return entities;
      }