docs: public DescribeRdsDbInstancesRequest withRdsDbInstanceArns(String... rdsDbInstanceArns) {
          if (this.rdsDbInstanceArns == null) {
              setRdsDbInstanceArns(new com.amazonaws.internal.SdkInternalList<String>(rdsDbInstanceArns.length));
          }
          for (String ele : rdsDbInstanceArns) {
              this.rdsDbInstanceArns.add(ele);
          }
          return this;
      }