code: public Discover primaryReleaseYear(int primaryReleaseYear) {
          if (checkYear(primaryReleaseYear)) {
              params.add(Param.PRIMARY_RELEASE_YEAR, primaryReleaseYear);
          }
          return this;
      }
docs: Filter the results so that only the primary release date year has this value
  
  @param primaryReleaseYear
  @return