docs: public UploadDocumentsResult withWarnings(DocumentServiceWarning... warnings) {
          if (this.warnings == null) {
              setWarnings(new com.amazonaws.internal.SdkInternalList<DocumentServiceWarning>(warnings.length));
          }
          for (DocumentServiceWarning ele : warnings) {
              this.warnings.add(ele);
          }
          return this;
      }