code: public Vector add(double value) {
          VectorIterator it = iterator();
          Vector result = blank();
  
          while (it.hasNext()) {
              double x = it.next();
              int i = it.index();
              result.set(i, x + value);
          }
  
          return result;
      }
docs: Adds given {@code value} (v) to this vector (X).
  
  @param value the right hand value for addition
  
  @return X + v