code: private QueryResultImpl combineResults(QueryResultImpl a, QueryResultImpl b, boolean distinct) {
          QueryResultImpl result = new QueryResultImpl(a.getQuery());
  
          for (QueryBindingImpl bindingA : a.getBindings()) {
              for (QueryBindingImpl bindingB : b.getBindings()) {
                  QueryBindingImpl binding = new QueryBindingImpl();
                  binding.set(bindingA);
                  binding.set(bindingB);
                  result.add(binding);
              }
          }
  
          if (distinct) {
              return eliminateDuplicates(result);
          }
          return result;
      }
docs: Combine two results with the cartesian product.
  
  @return the combined result