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