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: fieldnames.m
    path of file: ./repos/fieldtrip/external/gifti/@gifti
    
    the code of the file until where you have to start completion: function names = fieldnames(this)
% Fieldnames method for GIfTI objects
% FORMAT names = fieldnames(this)
% this   -  GIfTI object

    
function names = fieldnames(this)
% Fieldnames method for GIfTI objects
% FORMAT names = fieldnames(this)
% this   -  GIfTI object
% names  -  field names
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

% Guillaume Flandin
% $Id: fieldnames.m 6507 2015-07-24 16:48:02Z guillaume $

if numel(this) > 1, warning('Only handle scalar objects yet.'); end