@Override
    @Nullable
    public String getPrefixForURI(String uri, XmlElement context) {
      final BidirectionalMap<String, String> bidiMap = new BidirectionalMap<>();
      bidiMap.putAll(Namespace.makeMap(myNamespaceTableModel.getNamespaces()));
      final List<String> list = bidiMap.getKeysByValue(uri);
      return list != null && list.size() > 0 ? list.get(0) : null;
    }
@Override
    @Nullable
    public String getPrefixForURI(String uri, XmlElement context)