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: tutorial_yokogawa.m
    path of file: ./repos/brainstorm3/toolbox/script
    
    the code of the file until where you have to start completion: function tutorial_yokogawa(tutorial_dir)
% TUTORIAL_YOKOGAWA: Script that reproduces the results of the online tutorials "Yokogawa recordings".
%
% CORRESPONDING ONLINE TUTORIALS:
%     https://neuroimage.usc.edu/brainstorm/Tutorials/Yokogawa
%
% INPUTS: 
%     tutorial_dir: Directory where the sample_yokogawa.zip file has been unzipped

% @=============================================================================
% This function is part of the Brainstorm software:
% https://neuroimage.usc.edu/brainstorm
% 
% Copyright (c) University of Southern California & McGill University
% This software is distributed under the terms of the GNU General Public License
% as published by the Free Software Foundation. Further details on the GPLv3
% license can be found at http://www.gnu.org/copyleft/gpl.html.
% 
% FOR RESEARCH PURPOSES ONLY. THE SOFTWARE IS PROVIDED "AS IS," AND THE

    
function tutorial_yokogawa(tutorial_dir)
% TUTORIAL_YOKOGAWA: Script that reproduces the results of the online tutorials "Yokogawa recordings".
%
% CORRESPONDING ONLINE TUTORIALS:
%     https://neuroimage.usc.edu/brainstorm/Tutorials/Yokogawa
%
% INPUTS: 
%     tutorial_dir: Directory where the sample_yokogawa.zip file has been unzipped

% @=============================================================================
% This function is part of the Brainstorm software:
% https://neuroimage.usc.edu/brainstorm
% 
% Copyright (c) University of Southern California & McGill University
% This software is distributed under the terms of the GNU General Public License
% as published by the Free Software Foundation. Further details on the GPLv3
% license can be found at http://www.gnu.org/copyleft/gpl.html.
% 
% FOR RESEARCH PURPOSES ONLY. THE SOFTWARE IS PROVIDED "AS IS," AND THE
% UNIVERSITY OF SOUTHERN CALIFORNIA AND ITS COLLABORATORS DO NOT MAKE ANY
% WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF
% MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, NOR DO THEY ASSUME ANY
% LIABILITY OR RESPONSIBILITY FOR THE USE OF THIS SOFTWARE.
%
% For more information type "brainstorm license" at command prompt.
% =============================================================================@
%
% Author: Francois Tadel, 2014-2016


% ======= FILES TO IMPORT =======
% You have to specify the folder in which the tutorial dataset is unzipped
if (nargin == 0) || isempty(tutorial_dir) || ~file_exist(tutorial_dir)
    error('The first argument must be the full path to the tutorial dataset folder.');
end
% Build the path of the files to import
AnatDir = fullfile(tutorial_dir, 'sample_yokogawa', 'anatomy', 'freesurfer');
RawFile = fullfile(tutorial_dir, 'sample_yokogawa', 'data', 'SEF_000-export.con');
% Check if the folder contains the required files
if ~file_exist(RawFile)
    error(['The folder ' tutorial_dir ' does not contain the folder from the file sample_yokogawa.zip.']);
end