code: public List<T> apply(List<T> selectedCandidates, Random rng)
      {
          return new ArrayList<T>(selectedCandidates);
      }
docs: Returns the selected candidates unaltered.
  @param selectedCandidates The candidates to "evolve" (or do
  nothing to in this case).
  @param rng A source of randomness (not used).
  @return The unaltered candidates.