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: varargin2struct.m
    path of file: ./repos/coursera-machine-learning/machine-learning-ex8/ex8/lib/jsonlab
    
    the code of the file until where you have to start completion: function opt=varargin2struct(varargin)
%

    
function opt=varargin2struct(varargin)
%
% opt=varargin2struct('param1',value1,'param2',value2,...)
%   or
% opt=varargin2struct(...,optstruct,...)
%
% convert a series of input parameters into a structure
%
% authors:Qianqian Fang (fangq<at> nmr.mgh.harvard.edu)
% date: 2012/12/22
%
% input:
%      'param', value: the input parameters should be pairs of a string and a value
%       optstruct: if a parameter is a struct, the fields will be merged to the output struct
%
% output:
%      opt: a struct where opt.param1=value1, opt.param2=value2 ...
%
% license:
%     BSD, see LICENSE_BSD.txt files for details 
%
% -- this function is part of jsonlab toolbox (http://iso2mesh.sf.net/cgi-bin/index.cgi?jsonlab)
%

len=length(varargin);
opt=struct;
if(len==0) return; end