code: @SuppressWarnings("unchecked")
    public static <E, C extends Counter<E>> C scale(C c, double s) {
      C scaled = (C) c.getFactory().create();
      for (E key : c.keySet()) {
        scaled.setCount(key, c.getCount(key) * s);
      }
      return scaled;
    }
docs: Returns a new Counter which is scaled by the given scale factor.
  
  @param c
  The counter to scale. It is not changed
  @param s
  The constant to scale the counter by
  @return A new Counter which is the argument scaled by the given scale
  factor.