code: public static SingleItemSketch create(final long datum, final long seed) {
      final long[] data = { datum };
      return new SingleItemSketch(hash(data, seed)[0] >>> 1);
    }
docs: Create this sketch with a long and a seed.
  
  @param datum The given long datum.
  @param seed used to hash the given value.
  @return a SingleItemSketch