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: bspm_level2_tstt.m
    path of file: ./repos/bspm/level2
    
    the code of the file until where you have to start completion: function matlabbatch = bspm_level2_tstt(cons1, cons2, varargin)
% BSPM_LEVEL2_TSTT
%

    
function matlabbatch = bspm_level2_tstt(cons1, cons2, varargin)
% BSPM_LEVEL2_TSTT
%
%   ARGUMENTS:
%       cons1: contrast images from level 1 for group 1
%       cons2: contrast images from level 1 for group 2
%       grouplabels: labels for group 1 and group 2 (e.g., {'group1' 'group2'})
%       covariates: specified as follows:
%           covariates(n).name = 'Covariate Name';
%           covariates(n).values = [1...n];
%

% -------------------------- Copyright (C) 2014 --------------------------
%	Author: Bob Spunt
%	Affilitation: Caltech
%	Email: spunt@caltech.edu
%
%	$Revision Date: Aug_20_2014
def =   { ...
        'outdir',       [],                     ...
        'grouplabels',  {'Group1' 'Group2'},    ...
        'tag',          [],                     ...
        'implicitmask',  1,                     ...
        'omitpat',      {''},   ...
        'mask',         '',                     ...
        'pctgroup',     [],                     ...
        'viewit',        0,                     ...
        'negativecon',   0,                     ...
        'nan2zero',      0,                     ...
        'covariates',   []                      ...
        };
vals = setargs(def, varargin);
if nargin<2, mfile_showhelp; fprintf('\t= DEFAULT SETTINGS =\n'); disp(vals); return; end