@Override
 public KeywordSubstitutionWrapper valueOf(FileExtension extension) {
   return extension.getKeywordSubstitution();
 }
 @Override
 public void setValue(FileExtension extension, KeywordSubstitutionWrapper aValue) {
   extension.setKeywordSubstitution(aValue);
 }
 @Override
 public String valueOf(FileExtension o) {
   return o.getExtension();
 }