code: @SuppressWarnings("unchecked")
  	public <T> UnsortedGrouping<T> getUnsortedGrouping(int id) {
  		return verifyType(id, unsortedGroupings.get(id), SetType.UNSORTED_GROUPING);
  	}
docs: Returns the cached {@link UnsortedGrouping} for the given ID.
  
  @param id  Set ID
  @param <T> UnsortedGrouping type
  @return Cached UnsortedGrouping
  @throws IllegalStateException if the cached set is not an UnsortedGrouping