function output = myAdd(varargin)

    switch nargin
        case 0
            disp('Usage: ...');
        case 1
            output = varargin{1};
        case 2
            output = varargin{1} + varargin{2};
        case 3
            output = sum([varargin{:}]);
        otherwise
            error('Too many input arguments qq.')
    end
    
end