docs: public GetCostAndUsageResult withGroupDefinitions(GroupDefinition... groupDefinitions) {
          if (this.groupDefinitions == null) {
              setGroupDefinitions(new java.util.ArrayList<GroupDefinition>(groupDefinitions.length));
          }
          for (GroupDefinition ele : groupDefinitions) {
              this.groupDefinitions.add(ele);
          }
          return this;
      }