function write(x, file)
% WRITE  Write XML_Node to file.
% write(x, file)
%
% :param x:
%     Instance of class :mat:func:`XML_Node`
% :param file:
%     Name of the output file to be written.
% :return:
%     Instance of class :mat:func:`XML_Node`
%

ctmethods(10, 13, x.id, file);