You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: set_order_options.m
    path of file: ./repos/gramm/@gramm
    
    the code of the file until where you have to start completion: function obj=set_order_options(obj,varargin)
% set_order_options() Set ordering options for categorical
% variables

    
function obj=set_order_options(obj,varargin)
% set_order_options() Set ordering options for categorical
% variables
%
% Ordering options are available for 'x', 'color', 'marker',
% 'size', 'linestyle', 'row', 'column', 'lightness'
% For each variable, the option is provided with a 'name',
% value pair. Example for setting the ordering for the 'color' variable:
%
% 'color',1     This is the default, orders  variable in
% ascend