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: bsscca.m
    path of file: ./repos/fieldtrip/private
    
    the code of the file until where you have to start completion: function [unmixing, mixing, rho, compdata, time] = bsscca(X, varargin)

% BSSCCA computes the unmixing matrix based on the canonical correlation between 
% two sets of (possibly multivariate) signals, the sets may contain time shifted copies. 
% In its default, it implements the algorithm described in [1], computing the
% canonical correlation between a set of signals and their lag-one-shifted
% copy. Alternatively, if the input contains a reference signal (possibly multivariate),
% the canonical correlation between the data in X and the reference signal is computed.
% It requires JM's cellfunction toolbox on the MATLAB path:
%  (github.com/schoffelen/cellfunction.git)
%
% [1] DeClercq et al 2006, IEEE Biomed Eng 2583.

    
function [unmixing, mixing, rho, compdata, time] = bsscca(X, varargin)

% BSSCCA computes the unmixing matrix based on the canonical correlation between 
% two sets of (possibly multivariate) signals, the sets may contain time shifted copies. 
% In its default, it implements the algorithm described in [1], computing the
% canonical correlation between a set of signals and their lag-one-shifted
% copy. Alternatively, if the input contains a reference signal (possibly multivariate),
% the canonical correlation between the data in X and the reference signal is computed.
% It requires JM's cellfunction toolbox on the MATLAB path:
%  (github.com/schoffelen/cellfunction.git)
%
% [1] DeClercq et al 2006, IEEE Biomed Eng 2583.

% Copyright (C) 2017, Jan-Mathijs Schoffelen

if isa(X, 'cell')
  n = size(X{1},1);
else
  n = size(X,1);
end