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_branch.m
    path of file: ./repos/fieldtrip/external/spm12/matlabbatch/@cfg_branch
    
    the code of the file until where you have to start completion: function item = cfg_branch(varargin)

% This is the branch configuration item class for non-executable
% branches. It implements branch harvest, all_set, get_strings.
%
% Data structure
% ==============
% Description fields
%    * name  - display name of config item
%    * tag   - tag of the menu item
%    * val   - 1xn cell array of cfg_item objects
%    * 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 are inherited from the generic configuration item class.
%
% Public Methods
% ==============
%    * get_strings - returns name of object
%    * gettag      - returns tag
%    * help        - returns help text
%    * harvest     - returns struct, field names correspond to tags of
%                    items in .val field
%    * all_set     - returns all(all_set(item.val{...}))
%
% Output in Job Structure (harvest)
% =================================
% The resulting structure is a struct. Its fieldnames correspond to the
% tags of the cfg_items in item.val, the value of each field is the
% harvested data of the corresponding child item.
%
% 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.
%
%   The resulting data structure is a struct, with fieldnames according
%   to the 'tag's of the child nodes.
%
% 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_branch.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_intree'}]))
            gitem = varargin{1}.cfg_item;

    
function item = cfg_branch(varargin)

% This is the branch configuration item class for non-executable
% branches. It implements branch harvest, all_set, get_strings.
%
% Data structure
% ==============
% Description fields
%    * name  - display name of config item
%    * tag   - tag of the menu item
%    * val   - 1xn cell array of cfg_item objects
%    * 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 are inherited from the generic configuration item class.
%
% Public Methods
% ==============
%    * get_strings - returns name of object
%    * gettag      - returns tag
%    * help        - returns help text
%    * harvest     - returns struct, field names correspond to tags of
%                    items in .val field
%    * all_set     - returns all(all_set(item.val{...}))
%
% Output in Job Structure (harvest)
% =================================
% The resulting structure is a struct. Its fieldnames correspond to the
% tags of the cfg_items in item.val, the value of each field is the
% harvested data of the corresponding child item.
%
% 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.
%
%   The resulting data structure is a struct, with fieldnames according
%   to the 'tag's of the child nodes.
%
% 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_branch.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_intree'}]))
            gitem = varargin{1}.cfg_item;
            sitem = rmfield(varargin{1},{'cfg_item','cfg_intree'});
            item  = class(sitem, myclass, gitem, cfg_intree);
            return;
        else
            cfg_message('matlabbatch:constructor:reclassify', ['Don''t know how to convert this ' ...
                                'into class ''%s''.'], myclass);
        end