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: bf_sources_scalp.m
    path of file: ./repos/spm/toolbox/DAiSS
    
    the code of the file until where you have to start completion: function mesh = bf_sources_scalp(BF, S)
% Generate source space on the scalp surface, as a part of measuring a

    
function mesh = bf_sources_scalp(BF, S)
% Generate source space on the scalp surface, as a part of measuring a
% magnetomyogram (MMG) of the face.
% 
% See https://doi.org/10.1111/psyp.13507 for more information.
%__________________________________________________________________________


% George O'Neill
% Copyright (C) 2022-2023 Wellcome Centre for Human Neuroimaging

if nargin == 0
    
    orient         = cfg_menu;
    orient.tag     = 'orient';
    orient.name    = 'How to orient the sources';
    orient.labels  = {'Unoriented', 'Original'};
    orient.values  = {'unoriented', 'original'};
    orient.val     = {'unoriented'};
    
%     warp           = cfg_menu;
%     warp.tag       = 'warp';
%     warp.name      = 'How to warp between canonical and individual mesh';
%     warp.labels    = {'Affine Transform', 'Deformation Field'};
%     warp.values    = {'affine','def'};
%     warp.val       = {'affine'};
%     
    mesh = cfg_branch;
    mesh.tag = 'scalp';
    mesh.name = 'Scalp mesh';
    mesh.val = {orient};
    
    return
elseif nargin < 2
    error('Two input arguments are required');
end