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: BaseLine2.m
    path of file: ./repos/OSET/matlab/tools/emg
    
    the code of the file until where you have to start completion: function [x2] = BaseLine2(x,L1,L2,approach)
%
% b = BaseLine2(x,L1,L2,approach),
% Baseline wander extraction from biomedical recordings, using two stages 
% of median or moving average filtering.
%
% inputs:
% x: vector or matrix of noisy data (channels x samples)
% L1: first stage averaging window length (in samples)
% L2: second stage averaging window length (in samples)
% approach:
%   'md': median filtering
%   'mn': moving average
%

    
function [x2] = BaseLine2(x,L1,L2,approach)
%
% b = BaseLine2(x,L1,L2,approach),
% Baseline wander extraction from biomedical recordings, using two stages 
% of median or moving average filtering.
%
% inputs:
% x: vector or matrix of noisy data (channels x samples)
% L1: first stage averaging window length (in samples)
% L2: second stage averaging window length (in samples)
% approach:
%   'md': median filtering
%   'mn': moving average
%
% output:
% b: vector or matrix of baseline wanders (channels x samples)
%
%
% Open Source ECG Toolbox, version 1.0, November 2006
% Released under the GNU General Public License
% Copyright (C) 2006  Reza Sameni
% Sharif University of Technology, Tehran, Iran -- GIPSA-Lab, INPG, Grenoble, France
% reza.sameni@gmail.com

% This program 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 2 of the License, or (at your
% option) any later version.
% This program 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.

N = size(x,2);
x1 = zeros(size(x));
x2 = zeros(size(x));

flen1 = floor(L1/2);
flen2 = floor(L2/2);

if (strcmp(approach,'mn'))
    for j = 1:N,
        index = max(j-flen1,1):min(j+flen1,N);
        x1(:,j) = mean(x(:,index),2);
    end