@Override
  public String toString(final List<T> ts, final @NotNull ConvertContext context) {
    final StringBuilder buffer = new StringBuilder();
    final char delimiter = getDefaultDelimiter();
    for (T t : ts) {
      final String s = toString(t);
      if (s != null) {
        if (buffer.length() != 0) {
          buffer.append(delimiter);
        }
        buffer.append(s);
      }
    }
    return buffer.toString();
  }
@Override
  public String toString(final List<T> ts, final @NotNull ConvertContext context)