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_select_box.m
    path of file: ./repos/fecgsyn/subfunctions/data-generation/libs/fieldtrip/plotting
    
    the code of the file until where you have to start completion: function [x, y] = ft_select_box(handle, eventdata, varargin)

% FT_SELECT_BOX helper function for selecting a rectangular region
% in the current figure using the mouse.
%
% Use as
%   [x, y] = ft_select_box(...)
%
% It returns a 2-element vector x and a 2-element vector y
% with the corners of the selected region.
%
% Optional input arguments should come in key-value pairs and can include
%   'multiple' = true/false, make multiple selections by dragging, clicking
%                in one will finalize the selection (default = false)
%
% See also FT_SELECT_CHANNEL, FT_SELECT_POINT, FT_SELECT_POINT3D, FT_SELECT_RANGE, FT_SELECT_VOXEL 

% Copyright (C) 2006, Robert Oostenveld
%
% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org
% 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

    
function [x, y] = ft_select_box(handle, eventdata, varargin)

% FT_SELECT_BOX helper function for selecting a rectangular region
% in the current figure using the mouse.
%
% Use as
%   [x, y] = ft_select_box(...)
%
% It returns a 2-element vector x and a 2-element vector y
% with the corners of the selected region.
%
% Optional input arguments should come in key-value pairs and can include
%   'multiple' = true/false, make multiple selections by dragging, clicking
%                in one will finalize the selection (default = false)
%
% See also FT_SELECT_CHANNEL, FT_SELECT_POINT, FT_SELECT_POINT3D, FT_SELECT_RANGE, FT_SELECT_VOXEL 

% Copyright (C) 2006, Robert Oostenveld
%
% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org
% 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/>.
%
% $Id$

% get the optional arguments
multiple = ft_getopt(varargin, 'multiple', false);

if istrue(multiple)
  ft_error('not yet implemented');
else
  k = waitforbuttonpress;
  point1 = get(gca,'CurrentPoint');    % button down detected
  finalRect = rbbox;                   % return figure units
  point2 = get(gca,'CurrentPoint');    % button up detected
  point1 = point1(1,1:2);              % extract x and y
  point2 = point2(1,1:2);
  x = sort([point1(1) point2(1)]);
  y = sort([point1(2) point2(2)]);
end