code: @Override
      protected void writeETF(PrintWriter pw, DFA<?, I> dfa, Alphabet<I> inputs) {
          writeETFInternal(pw, dfa, inputs);
      }
docs: Write DFA specific parts in the ETF.
  
  - initial state,
  - the valuations for the state 'id',
  - the letters in the alphabet,
  - the transitions,
  - the state labels (rejecting/accepting),
  - the mapping from states to state labels.
  
  @param pw the Writer.
  @param dfa the DFA to write.
  @param inputs the alphabet.