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: vander.m
    path of file: ./repos/chebfun/@chebfun
    
    the code of the file until where you have to start completion: function A = vander(f, n)
%VANDER   Vandermonde array-valued CHEBFUN.
%   A = VANDER(F, N) returns a Vandermonde array-valued CHEBFUN whose N columns

    
function A = vander(f, n)
%VANDER   Vandermonde array-valued CHEBFUN.
%   A = VANDER(F, N) returns a Vandermonde array-valued CHEBFUN whose N columns
%   are powers of the CHEBFUN F, that is A(:,j) = F.^(N-j), j = 0...N-1.

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

if ( f(1).isTransposed || numColumns(f) > 1 )
    error('CHEBFUN:CHEBFUN:vander:row', ...
        'Input must be a scalar-valued column CHEBFUN.')
end