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: spm_match_str.m
    path of file: ./repos/ExploreASL/External/SPMmodified
    
    the code of the file until where you have to start completion: function [sel1, sel2] = spm_match_str(a, b)
% MATCH_STR looks for matching labels in two listst of strings
% and returns the indices into both the 1st and 2nd list of the matches.
% They will be ordered according to the first input argument.
%  
% [sel1, sel2] = match_str(strlist1, strlist2)
%
% The strings can be stored as a char matrix or as an vertical array of
% cells, the matching is done for each row.
%_______________________________________________________________________
% Copyright (C) 2000, Robert Oostenveld

% Robert Oostenveld

    
function [sel1, sel2] = spm_match_str(a, b)
% MATCH_STR looks for matching labels in two listst of strings
% and returns the indices into both the 1st and 2nd list of the matches.
% They will be ordered according to the first input argument.
%  
% [sel1, sel2] = match_str(strlist1, strlist2)
%
% The strings can be stored as a char matrix or as an vertical array of
% cells, the matching is done for each row.
%_______________________________________________________________________
% Copyright (C) 2000, Robert Oostenveld

% Robert Oostenveld
% $Id: spm_match_str.m 3589 2009-11-20 17:17:41Z guillaume $

% ensure that both are cell-arrays
if isempty(a)
  a = {};
elseif ~iscell(a)
  a = cellstr(a);
end