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: prplot.m
    path of file: ./repos/CanlabCore/CanlabCore/Visualization_functions
    
    the code of the file until where you have to start completion: function [r,str,sig,ry,rx,h,rr] = prplot(yy,X,k,varargin)

% Partial residual plot of y ~ X for column k
% Partial residual plot of one column of X against y. Uses IRLS estimation 
% to downweight outliers if you enter a 4th argument.
% 
% :Usage:
% ::
%
%    [r,str,sig,ry,rx,h,rr] = prplot(y,X,col,[dorobust],[colors])
%
% ..
%     Author and copyright information:
%
%     Copyright (C) Tor Wager
%
%     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 3 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.
%
%     You should have received a copy of the GNU General Public License
%     along with this program.  If not, see <http://www.gnu.org/licenses/>.
% ..
%
% :Inputs:
%   **y** 
%       if y contains multiple columns, different colors and symbols will 

    
function [r,str,sig,ry,rx,h,rr] = prplot(yy,X,k,varargin)

% Partial residual plot of y ~ X for column k
% Partial residual plot of one column of X against y. Uses IRLS estimation 
% to downweight outliers if you enter a 4th argument.
% 
% :Usage:
% ::
%
%    [r,str,sig,ry,rx,h,rr] = prplot(y,X,col,[dorobust],[colors])
%
% ..
%     Author and copyright information:
%
%     Copyright (C) Tor Wager
%
%     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 3 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.
%
%     You should have received a copy of the GNU General Public License
%     along with this program.  If not, see <http://www.gnu.org/licenses/>.
% ..
%
% :Inputs:
%   **y** 
%       if y contains multiple columns, different colors and symbols will 
%       be used, with a separate regression for each.
%
%   **colors**
%       e.g., {'ro' 'bs' 'gd' 'y^' 'cv' 'mx'}
%


mycols = {'ko'};
robopt = 'IRLS';    %'IRLS' or 'MCD'

if size(yy,2) > 1, 
    
        legstr = cell(1);
        mycols = {'ro' 'bs' 'gd' 'y^' 'cv' 'mx'};
        
end