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: test4.m
    path of file: ./repos/SuiteSparse/CHOLMOD/MATLAB/Test
    
    the code of the file until where you have to start completion: function test4
%TEST4 test cholmod2 with multiple and sparse right-hand-sides
% Example:
%   test4
% See also cholmod_test

% Copyright 2006-2023, Timothy A. Davis, All Rights Reserved.
% SPDX-License-Identifier: GPL-2.0+

fprintf ('=================================================================\n');
fprintf ('test4: test cholmod2 with multiple and sparse right-hand-sides\n') ;

Prob = ssget ('HB/bcsstk01') ;
A = Prob.A ;
n = size (A,1) ;

    
function test4
%TEST4 test cholmod2 with multiple and sparse right-hand-sides
% Example:
%   test4
% See also cholmod_test

% Copyright 2006-2023, Timothy A. Davis, All Rights Reserved.
% SPDX-License-Identifier: GPL-2.0+

fprintf ('=================================================================\n');
fprintf ('test4: test cholmod2 with multiple and sparse right-hand-sides\n') ;

Prob = ssget ('HB/bcsstk01') ;
A = Prob.A ;
n = size (A,1) ;
b = rand (n,1) ;
x = cholmod2 (A,b) ;
m2 = norm (A*x-b,1) ;
b = sparse (b) ;
x = cholmod2 (A,b) ;
m2 = max (m2, norm (A*x-b,1)) ;
m1 = 0 ;

for nrhs = 1:80
    b = sparse (rand (n,nrhs)) ;
    x = A\b ;
    e1 = norm (A*x-b,1) ;
    x = cholmod2 (A,b) ;
    e2 = norm (A*x-b,1) ;
    if (e2 > 1e-11)
        error ('!') ;
    end