code: public SortingParams by(final byte[] pattern) {
      params.add(BY.raw);
      params.add(pattern);
      return this;
    }
docs: Sort by weight in keys.
  <p>
  Takes a pattern that is used in order to generate the key names of the weights used for
  sorting. Weight key names are obtained substituting the first occurrence of * with the actual
  value of the elements on the list.
  <p>
  The pattern for a normal key/value pair is "field*" and for a value in a hash
  "field*-&gt;fieldname".
  @param pattern
  @return the SortingParams Object