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: isfunction.m
    path of file: ./repos/bspm/thirdparty/spm12/external/fieldtrip/private
    
    the code of the file until where you have to start completion: function b = isfunction(funcname)

% ISFUNCTION tests whether the function of the specified name is a callable
% function on the current MATLAB path.
%

    
function b = isfunction(funcname)

% ISFUNCTION tests whether the function of the specified name is a callable
% function on the current MATLAB path.
%
% Note that this is *not* equivalent to calling exist(funcname, 'file'),
% since that will return 7 in case funcname exists as a folder.

b = ~isempty(which(funcname));
end