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: divergence.m
    path of file: ./repos/chebfun/@chebfun2v
    
    the code of the file until where you have to start completion: function f = divergence(F)
%DIVERGENCE   Divergence of a CHEBFUN2V.

    
function f = divergence(F)
%DIVERGENCE   Divergence of a CHEBFUN2V.
%   DIVERGENCE(F) returns the divergence of the CHEBFUN2V i.e.,
%       divergence(F) = F_x + F_y.
%
% See also DIV.

% Copyright 2017 by The University of Oxford and The Chebfun Developers.
% See http://www.chebfun.org/ for Chebfun information. 

% Note that the divergence of a 3-vector is the same, because the functions are
% of two variables.

% Empty check: 
if ( isempty( F ) )
    f = chebfun2;
    return
end