code: public Discover sortBy(SortBy sortBy) {
          params.add(Param.SORT_BY, sortBy.getPropertyString());
          return this;
      }
docs: Available options are <br>
  vote_average.desc<br>
  vote_average.asc<br>
  release_date.desc<br>
  release_date.asc<br>
  popularity.desc<br>
  popularity.asc
  
  @param sortBy
  @return