code: public static <E> Counter<E> multiplyInPlace(Counter<E> target, double multiplier) {
      for (Entry<E, Double> entry : target.entrySet()) {
        target.setCount(entry.getKey(), entry.getValue() * multiplier);
      }
      return target;
    }
docs: Multiplies each value in target by the given multiplier, in place.
  
  @param target
  The values in this Counter will be changed throught by the
  multiplier
  @param multiplier
  The number by which to change each number in the Counter