code: void addTransition(CharRange condition, DFAState<T> to)
      {
          Transition<DFAState<T>> t = new Transition<>(condition, this, to);
          t = transitions.put(t.getCondition(), t);
          assert t == null;
          edges.add(to);
          to.inStates.add(this);
      }
docs: Adds a new transition
  @param condition
  @param to