docs: function (dataset, opts) {
              opts = isUndefined(opts) ? {} : opts;
              if (!isHash(opts)) {
                  opts = {all: opts};
              }
              if (!this.supportsIntersectExcept) {
                  throw new QueryError("INTERSECT not supported");
              } else if (opts.all && !this.supportsIntersectExceptAll) {
                  throw new QueryError("INTERSECT ALL not supported");
              }
              return this.compoundClone("intersect", dataset, opts);
          }