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: out_channel_brainsight.m
    path of file: ./repos/brainstorm3/toolbox/io
    
    the code of the file until where you have to start completion: function out_channel_brainsight(BstFile, OutputFile, Factor, Transf)
% OUT_CHANNEL_BRAINSIGHT: Export a Brainstorm channel file in
% brainsight coordinate files.
%
% USAGE:  out_channel_brainsight( BstFile, OutputFile, Factor, Transf)
%
% INPUT:
%     - BstFile    : full path to Brainstorm file to export
%     - OutputFile : full path to output file
%     - Factor     : Factor to convert the positions values in meters.
%     - Transf     : 4x4 transformation matrix to apply to the 3D positions before saving
%                    or entire MRI structure. Optodes are
%                    exported using world coordinates.
%
% @=============================================================================
% 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.
% =============================================================================@
%
% Authors: Thomas Vincent 2017, Edouard Delaire 2023

    
function out_channel_brainsight(BstFile, OutputFile, Factor, Transf)
% OUT_CHANNEL_BRAINSIGHT: Export a Brainstorm channel file in
% brainsight coordinate files.
%
% USAGE:  out_channel_brainsight( BstFile, OutputFile, Factor, Transf)
%
% INPUT:
%     - BstFile    : full path to Brainstorm file to export
%     - OutputFile : full path to output file
%     - Factor     : Factor to convert the positions values in meters.
%     - Transf     : 4x4 transformation matrix to apply to the 3D positions before saving
%                    or entire MRI structure. Optodes are
%                    exported using world coordinates.
%
% @=============================================================================
% 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.
% =============================================================================@
%
% Authors: Thomas Vincent 2017, Edouard Delaire 2023

if (nargin < 3) || isempty(Factor)
    Factor = .001;
end
if (nargin < 4) || isempty(Transf)
    Transf = [];
end


% Load brainstorm channel file
if ischar(BstFile)
    ChannelMat = in_bst_channel(BstFile);
else
    ChannelMat = BstFile;
end