@Nullable
  private IElementType parseItemOrEmptySequenceType(PsiBuilder builder) {
    final IElementType tokenType = builder.getTokenType();
    if (tokenType == XPath2TokenTypes.ITEM || tokenType == XPath2TokenTypes.EMPTY_SEQUENCE) {
      final PsiBuilder.Marker mark = builder.mark();
      builder.advanceLexer();
      parseArgumentList(builder);
      mark.done(XPath2ElementTypes.ITEM_OR_EMPTY_SEQUENCE);
      return tokenType;
    }
    return null;
  }
@Nullable
  private IElementType parseItemOrEmptySequenceType(PsiBuilder builder)