code: public static <S> boolean acceptsEmptyLanguage(DFA<S, ?> dfa) {
          return dfa.getStates().stream().noneMatch(dfa::isAccepting);
      }
docs: Computes whether the given {@link DFA} accepts the empty language.
  
  Assumes all states in the given {@link DFA} are reachable from the initial state.
  
  @param dfa the {@link DFA} to check.
  @param <S> the state type.
  
  @return whether the given {@link DFA} accepts the empty language.