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: save_untouch_slice.m
    path of file: ./repos/malini/NIFTI
    
    the code of the file until where you have to start completion: %  Save back to the original image with a portion of slices that was
%  loaded by "load_untouch_nii". You can process those slices matrix
%  in any way, as long as their dimension is not altered.
%
%  Usage: save_untouch_slice(slice, filename, ...
%		slice_idx, [img_idx], [dim5_idx], [dim6_idx], [dim7_idx])
%
%  slice  -  a portion of slices that was loaded by "load_untouch_nii".
%	This should be a numeric matrix (i.e. only the .img field in the
%	loaded structure)
%
%  filename  - 	NIfTI or ANALYZE file name.
%
%  slice_idx (depending on slice size)  -  a numerical array of image
%	slice indices, which should be the same as that you entered
%	in "load_untouch_nii" command.
%
%  img_idx (depending on slice size)  -  a numerical array of image
%	volume indices, which should be the same as that you entered
%	in "load_untouch_nii" command.
%
%  dim5_idx (depending on slice size)  -  a numerical array of 5th 
%	dimension indices, whi
    
function save_untouch_slice_img(slice,hdr,filetype,fileprefix,machine,slice_idx,img_idx,dim5_idx,dim6_idx,dim7_idx)

   if ~exist('hdr','var') | ~exist('filetype','var') | ~exist('fileprefix','var') | ~exist('machine','var')
      error('Usage: save_untouch_slice_img(slice,hdr,filetype,fileprefix,machine,slice_idx,[img_idx],[dim5_idx],[dim6_idx],[dim7_idx]);');
   end

   if ~exist('slice_idx','var') | isempty(slice_idx) | hdr.dime.dim(4)<1
      slice_idx = [];
   end

   if ~exist('img_idx','var') | isempty(img_idx) | hdr.dime.dim(5)<1
      img_idx = [];
   end

   if ~exist('dim5_idx','var') | isempty(dim5_idx) | hdr.dime.dim(6)<1
      dim5_idx = [];
   end

   if ~exist('dim6_idx','var') | isempty(dim6_idx) | hdr.dime.dim(7)<1
      dim6_idx = [];
   end

   if ~exist('dim7_idx','var') | isempty(dim7_idx) | hdr.dime.dim(8)<1
      dim7_idx = [];
   end

   %  check img_idx
   %
   if ~isempty(img_idx) & ~isnumeric(img_idx)
      error('"img_idx" should be a numerical array.');
   end

   if length(unique(img_idx)) ~= length(img_idx)
      error('Duplicate image index in "img_idx"');
   end