code: public static Taint valueOf(State state) {
          Objects.requireNonNull(state, "state is null");
          if (state == State.INVALID) {
              return null;
          }
          return new Taint(state);
      }
docs: Constructs a new instance of taint from the specified state
  
  @param state the specified state
  @return the constructed instance
  @throws NullPointerException if state is null