docs: protected AttachedFileDataType[] getAppendixAttachedFileDataTypes() {
          return pdDoc.getDevelopmentProposal().getNarratives().stream()
                  .filter(narrative -> narrative.getNarrativeType().getCode() != null && Integer.parseInt(narrative.getNarrativeType().getCode()) == APPENDIX)
                  .map(this::getAttachedFileType)
                  .filter(Objects::nonNull)
                  .toArray(AttachedFileDataType[]::new);
      }