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: spm_sixel.m
    path of file: ./repos/spm
    
    the code of the file until where you have to start completion: function spm_sixel(img,col,filename)
% Display or export images in sixel format
% FORMAT spm_sixel(img,col,[filename])
% img       - m x n indexed image or m x n x 3 RGB image
% col       - colormap (three-column matrix of RGB triplets)
% filename  - output filename [default: stdout]
%
% See https://en.wikipedia.org/wiki/Sixel
%__________________________________________________________________________
%
% r = spm_read_vols(spm_vol(fullfile(spm('Dir'),'tpm','TPM.nii,1')));

    
function spm_sixel(img,col,filename)
% Display or export images in sixel format
% FORMAT spm_sixel(img,col,[filename])
% img       - m x n indexed image or m x n x 3 RGB image
% col       - colormap (three-column matrix of RGB triplets)
% filename  - output filename [default: stdout]
%
% See https://en.wikipedia.org/wiki/Sixel
%__________________________________________________________________________
%
% r = spm_read_vols(spm_vol(fullfile(spm('Dir'),'tpm','TPM.nii,1')));
% g = spm_read_vols(spm_vol(fullfile(spm('Dir'),'tpm','TPM.nii,2')));
% b = spm_read_vols(spm_vol(fullfile(spm('Dir'),'tpm','TPM.nii,3')));
% [img,col] = rgb2ind(cat(3,r(:,:,50),g(:,:,50),b(:,:,50)),64);
% spm_sixel(img,col);
%__________________________________________________________________________

% Guillaume Flandin
% Copyright (C) 2020-2022 Wellcome Centre for Human Neuroimaging


%-Input arguments
%--------------------------------------------------------------------------
if ischar(img)
    img = spm_read_vols(spm_vol(img));
    % ANSI/VT100 Terminal Control Escape Sequences
    % http://www.termsys.demon.co.uk/vtansi.htm
    % See also clc, home and fprintf('\033[%dA',N) to move cursor up
    fprintf('\033[s');
    for z=1:size(img,3)
        spm_sixel(repmat(img(:,:,z),1,1,3));
        if z~=size(img,3), fprintf('\033[u'); end