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: saveNSx.m
    path of file: ./repos/fieldtrip/external/npmk/NSx Utilities
    
    the code of the file until where you have to start completion: function saveNSx(NSx,varargin)


    
function saveNSx(NSx,varargin)

%% 
% Save an .NSx file from an NSx structure (gained by using openNSx)
% Works with file spec 2.3
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Use: saveNSx(NSx,optionalinputarguments)
%   NSx:        The NSx data structure.
%   All arguments below are optional:
%   Filename:   A complete filepath for the output file.
%               Default: CurrentFilename-Modified.NSx

%saveNSx version = '1.0.0.0';


%% 
% Verify FilePath and establish overwrite paramaters
if not(isempty(varargin))
    FilePath = varargin{1};
else
    FilePath = [fullfile(NSx.MetaTags.FilePath,NSx.MetaTags.Filename) NSx.MetaTags.FileExt];
    [File,Path] = uiputfile;
    FilePath = [fullfile(Path,NSx.MetaTags.Filename(1:end)),'-modified',  NSx.MetaTags.FileExt];
end


disp('This script will save a new file with the proper .NSx extensions');
disp('but you should retain the previous file. Do you acknowledge the');
Accept = input('risk inherent in saving modified versions of data files? (Y/N)','s');
if strcmpi(Accept,'y')
else
    disp('Ending Script...');
    return
end