code: public static SingleItemSketch create(final byte[] data) {
      if ((data == null) || (data.length == 0)) { return null; }
      return new SingleItemSketch(hash(data, DEFAULT_UPDATE_SEED)[0] >>> 1);
    }
docs: Create this sketch with the given byte array.
  If the byte array is null or empty no create attempt is made and the method returns null.
  
  @param data The given byte array.
  @return a SingleItemSketch or null