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: fir_df.m
    path of file: ./repos/bspm/thirdparty/spm12/external/fieldtrip/preproc/private
    
    the code of the file until where you have to start completion: function [df, maxDf] = fir_df(cutoffArray, Fs)

% FIR_DF computes default and maximum possible transition band width from
% FIR filter cutoff frequency(ies)
%
% Use as
%   [df, maxDf] = fir_df(cutoffArray, Fs)
% where
%   cutoffArray filter cutoff frequency(ies)
%   Fs          sampling frequency in Hz
%
% Required filter order/transition band width is estimated with the
% following heuristic: transition band width is 25% of the lower cutoff
% frequency, but not lower than 2 Hz, where possible (for bandpass,
% highpass, and bandstop) and distance from passband edge to critical
% frequency (DC, Nyquist) otherwise. 
%
% See also FIRWS, FIRWSORD, INVFIRWSORD

% Copyright (c) 2014, Andreas Widmann
%
% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or

    
function [df, maxDf] = fir_df(cutoffArray, Fs)

% FIR_DF computes default and maximum possible transition band width from
% FIR filter cutoff frequency(ies)
%
% Use as
%   [df, maxDf] = fir_df(cutoffArray, Fs)
% where
%   cutoffArray filter cutoff frequency(ies)
%   Fs          sampling frequency in Hz
%
% Required filter order/transition band width is estimated with the
% following heuristic: transition band width is 25% of the lower cutoff
% frequency, but not lower than 2 Hz, where possible (for bandpass,
% highpass, and bandstop) and distance from passband edge to critical
% frequency (DC, Nyquist) otherwise. 
%
% See also FIRWS, FIRWSORD, INVFIRWSORD

% Copyright (c) 2014, Andreas Widmann
%
% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org
% for the documentation and details.
%
%    FieldTrip is free software: you can redistribute it and/or modify
%    it under the terms of the GNU General Public License as published by
%    the Free Software Foundation, either version 3 of the License, or
%    (at your option) any later version.
%
%    FieldTrip is distributed in the hope that it will be useful,
%    but WITHOUT ANY WARRANTY; without even the implied warranty of
%    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%    GNU General Public License for more details.
%
%    You should have received a copy of the GNU General Public License
%    along with FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id$

if nargin < 2 || isempty(cutoffArray) || isempty(Fs)
    ft_error('Not enough input arguments.')
end