docs: static <K> Map<K, Integer> getSlots(Map<Integer, ? extends Iterable<K>> partitioned) {
  
          Map<K, Integer> result = new HashMap<>();
          for (Map.Entry<Integer, ? extends Iterable<K>> entry : partitioned.entrySet()) {
              for (K key : entry.getValue()) {
                  result.put(key, entry.getKey());
              }
          }
  
          return result;
      }