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: cfg_menu.m
    path of file: ./repos/bspm/thirdparty/spm12/matlabbatch/@cfg_menu
    
    the code of the file until where you have to start completion: function item = cfg_menu(varargin)

% This is the menu configuration item class
%
% Data structure
% ==============
% Description fields
%    * name  - display name of config item
%    * tag   - tag of the menu item
%    * val   - 1x1 cell array
%    * check - (optional) function handle to implement configuration
%              specific subsasgn checks based on the harvested subtree

    
function item = cfg_menu(varargin)

% This is the menu configuration item class
%
% Data structure
% ==============
% Description fields
%    * name  - display name of config item
%    * tag   - tag of the menu item
%    * val   - 1x1 cell array
%    * check - (optional) function handle to implement configuration
%              specific subsasgn checks based on the harvested subtree
%              rooted at this node
%    * help  - help text
% GUI/job manager fields
%    * expanded
%    * hidden
% All fields above are inherited from the generic configuration item class.
%    * labels - cell array of label strings
%    * values - cell array of values
%    * def
%
% Public Methods
% ==============
%    * get_strings - returns name of object
%    * gettag      - returns tag
%    * help        - returns help text
%    * harvest     - returns item.val{1}, or '<UNDEFINED>' if empty, see below
%    * all_set     - returns ~isempty(item.val)
%
% Output in Job Structure (harvest)
% =================================
% cfg_menu uses cfg_item/harvest.
%
% The layout of the configuration tree and the types of configuration items
% have been kept compatible to a configuration system and job manager
% implementation in SPM5 (Statistical Parametric Mapping, Copyright (C)
% 2005 Wellcome Department of Imaging Neuroscience). This code has been
% completely rewritten based on an object oriented model of the
% configuration tree.
%
% This code is part of a batch job configuration system for MATLAB. See 
%      help matlabbatch
% for a general overview.
%_______________________________________________________________________
% Copyright (C) 2007 Freiburg Brain Imaging

% Volkmar Glauche
% $Id: cfg_menu.m 5678 2013-10-11 14:58:04Z volkmar $

rev = '$Rev: 5678 $'; %#ok

myclass = mfilename;
% Get local fields and defaults from private/mysubs_fields
[fn, defs] = mysubs_fields;

if nargin == 1
    if isstruct(varargin{1})
        % assume input is a struct to be converted back into a class
        % return with error if this does not work
        if numel(fieldnames(varargin{1})) == numel(fn)+2 && ...
                all(isfield(varargin{1}, [fn(:)', {'cfg_item' 'cfg_leaf'}]))
            gitem = varargin{1}.cfg_item;
            sitem = rmfield(varargin{1},{'cfg_item', 'cfg_leaf'});
            item  = class(sitem, myclass, gitem, cfg_leaf);
            return;
        else
            cfg_message('matlabbatch:constructor:reclassify', ['Don''t know how to convert this ' ...
                            'into class ''%s''.'], myclass);
        end