code: public Set<String> unique(@NonNull HString hString) {
        return stream(hString).collect(Collectors.toSet());
     }
docs: Executes the TermSpec returning a set of stringified terms. This method does not use the TermSpec's {@link
  com.davidbracewell.hermes.ml.feature.ValueCalculator}
  
  @param hString the HString to process
  @return a set of term counts