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: size.m
    path of file: ./repos/chebfun/@ballfunv
    
    the code of the file until where you have to start completion: function S = size(v)
% SIZE  Size of the expansion coefficients of a BALLFUNV
%   S = SIZE(V) returns a 3 by 3 matrix whose vertical entries represent

    
function S = size(v)
% SIZE  Size of the expansion coefficients of a BALLFUNV
%   S = SIZE(V) returns a 3 by 3 matrix whose vertical entries represent
%   the sizes of Vx, Vy and Vz
%
%   See also BALLFUN/SIZE.

% Copyright 2018 by The University of Oxford and The Chebfun Developers.
% See http://www.chebfun.org/ for Chebfun information.

% Return the list [m,n,p] corresponding to the size of the ballfun
% functions in f

if isempty( v )
    S = [];
    return
end