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: mtimes.m
    path of file: ./repos/chebfun/@chebtech
    
    the code of the file until where you have to start completion: function f = mtimes(f, c)
%*   Multiplication of CHEBTECH objects.
%   F*C or C*F multiplies a CHEBTECH F by a scalar or matrix C.
%
%   If F is an array-valued CHEBTECH and C is a matrix of appropriate dimension,
%   then the natural matrix multiplication is performed.
%
% See also TIMES.

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

if ( isempty(f) || isempty(c) )     % CHEBTECH * [] = []
    f = []; 
    return

    
function f = mtimes(f, c)
%*   Multiplication of CHEBTECH objects.
%   F*C or C*F multiplies a CHEBTECH F by a scalar or matrix C.
%
%   If F is an array-valued CHEBTECH and C is a matrix of appropriate dimension,
%   then the natural matrix multiplication is performed.
%
% See also TIMES.

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

if ( isempty(f) || isempty(c) )     % CHEBTECH * [] = []
    f = []; 
    return
    
elseif ( ~isa(f, 'chebtech') )      % CHEBTECH is not the first input
    % DOUBLE*CHEBTECH requires that the double is scalar.
    if ( numel(f) > 1 )
        error('CHEBFUN:CHEBTECH:mtimes:size', ...
            'Inner matrix dimensions must agree.');
    end