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: zscore.m
    path of file: ./repos/fieldtrip/external/cellfunction/@cell
    
    the code of the file until where you have to start completion: function [z, mu, s] = zscore(x, varargin)

% [Z, MU, S] = ZSCORE(X, NORMALIZEFLAG, DIM, FLAG) computes the zscore, across all cells in x along 
% the dimension dim, normalising by the total number of samples 

    
function [z, mu, s] = zscore(x, varargin)

% [Z, MU, S] = ZSCORE(X, NORMALIZEFLAG, DIM, FLAG) computes the zscore, across all cells in x along 
% the dimension dim, normalising by the total number of samples 
% 
% X should be an linear cell-array of matrices for which the size in at 
% least one of the dimensions should be the same for all cells. If flag==1, the mean will
% be subtracted first (default behavior, but to save time on already demeaned data, it
% can be set to 0). MU and S are vectors containing the mean and standard deviations used
% for zscoring

if numel(varargin)==0, varargin{1} = []; end