code: public IndexRequest sphereVersion(final Integer sphereVersion) {
          if (sphereVersion != null) {
              isTrueArgument("sphereIndexVersion must be 1, 2 or 3", VALID_SPHERE_INDEX_VERSIONS.contains(sphereVersion));
          }
          this.sphereVersion = sphereVersion;
          return this;
      }
docs: Sets the 2dsphere index version number.
  
  @param sphereVersion the 2dsphere index version number.
  @return this