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: ft_plot_topo3d.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/external/fieldtrip/plotting
    
    the code of the file until where you have to start completion: function ft_plot_topo3d(pnt, val, varargin)

% FT_PLOT_TOPO3D makes a 3-D topographic representation of the electric
% potential or field at the sensor locations
%
% Use as
%   ft_plot_topo3d(pos, val, ...);
% where the channel positions are given as a Nx3 matrix and the values are
% given as Nx1 vector.
%
% Optional input arguments should be specified in key-value pairs and can include
% 'contourstyle'  false  (default), 'black', 'color' makes contours of b/w or colored lines
% 'isocontour'    'auto' (default - and only - option)
% 'topostyle'     'color'(default - and only - option)

%
% See also FT_PLOT_TOPO
%
% Copyright (C) 2009, Robert Oostenveld
%
% This file is part of FieldTrip, see http://www.ru.nl/neuroimaging/fieldtrip
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip is distributed in the hope that it will be useful,
%    but WITHOUT ANY WARRANTY; without even the implied warranty of
%    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%    GNU General Public License for more details.
%
%    You should have received a copy of the GNU General Public License
%    along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id: ft_plot_topo3d.m 7123 2012-12-06 21:21:38Z roboos $


    
function ft_plot_topo3d(pnt, val, varargin)

% FT_PLOT_TOPO3D makes a 3-D topographic representation of the electric
% potential or field at the sensor locations
%
% Use as
%   ft_plot_topo3d(pos, val, ...);
% where the channel positions are given as a Nx3 matrix and the values are
% given as Nx1 vector.
%
% Optional input arguments should be specified in key-value pairs and can include
% 'contourstyle'  false  (default), 'black', 'color' makes contours of b/w or colored lines
% 'isocontour'    'auto' (default - and only - option)
% 'topostyle'     'color'(default - and only - option)

%
% See also FT_PLOT_TOPO
%
% Copyright (C) 2009, Robert Oostenveld
%
% This file is part of FieldTrip, see http://www.ru.nl/neuroimaging/fieldtrip
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip is distributed in the hope that it will be useful,
%    but WITHOUT ANY WARRANTY; without even the implied warranty of
%    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%    GNU General Public License for more details.
%
%    You should have received a copy of the GNU General Public License
%    along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id: ft_plot_topo3d.m 7123 2012-12-06 21:21:38Z roboos $

ws = warning('on', 'MATLAB:divideByZero');

% get the optional input arguments
contourstyle  = ft_getopt(varargin, 'contourstyle', false);
isocontour    = ft_getopt(varargin, 'isocontour',   'auto');
topostyle     = ft_getopt(varargin, 'topostyle',    'color');

% everything is added to the current figure
holdflag = ishold;
if ~holdflag
  hold on
end