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: xyrefline.m
    path of file: ./repos/malini/Classifiers/RLR/Classifier_Files/RLR
    
    the code of the file until where you have to start completion: function hh = xyrefline(x,varargin)
% XYREFLINE - Plot references lines
%   XYREFLINE(X) plots vertical reference lines at the positions specified
%   by X. XYREFLINE(X,Y) also plots horizontal references lines at the positions
%   specified by Y. XYREFLINE uses the current axes, if any. Lines outside
%   the plot area are plotted but not shown. When X or Y is empty no vertical
%   or horizontal lines are plotted.
%
%   The lines are plotted as a single graphics object. H = XYREFLINE(..) returns
%   a graphics handle to that line object. 
%
%   XYREFLINE(..., 'Prop1','Val1','Prop2','Val2', ...) uses the properties
%   and values specified for color, linestyle, etc. Execute GET(H), where H is
%   a line handle, to see a list of line object properties and their current values.
%   Execute SET(H) to see a list of line object properties and legal property values.
%
%   Examples
%     plot(10*rand(5),'bo') ;
%     xyrefline([1 3 4.5],'Color','r','Linestyle',':') ;
%     h = xyrefline([],[1:1.5:10],'Color',[0.4 0.3 0.5]) ;
%     set(h) ;
%
%   XYREFLINE can be used to plot a irregular grid on the axes.
%
%   See also PLOT, REFLINE, GRID, AXES

    
function hh = xyrefline(x,varargin)
% XYREFLINE - Plot references lines
%   XYREFLINE(X) plots vertical reference lines at the positions specified
%   by X. XYREFLINE(X,Y) also plots horizontal references lines at the positions
%   specified by Y. XYREFLINE uses the current axes, if any. Lines outside
%   the plot area are plotted but not shown. When X or Y is empty no vertical
%   or horizontal lines are plotted.
%
%   The lines are plotted as a single graphics object. H = XYREFLINE(..) returns
%   a graphics handle to that line object. 
%
%   XYREFLINE(..., 'Prop1','Val1','Prop2','Val2', ...) uses the properties
%   and values specified for color, linestyle, etc. Execute GET(H), where H is
%   a line handle, to see a list of line object properties and their current values.
%   Execute SET(H) to see a list of line object properties and legal property values.
%
%   Examples
%     plot(10*rand(5),'bo') ;
%     xyrefline([1 3 4.5],'Color','r','Linestyle',':') ;
%     h = xyrefline([],[1:1.5:10],'Color',[0.4 0.3 0.5]) ;
%     set(h) ;
%
%   XYREFLINE can be used to plot a irregular grid on the axes.
%
%   See also PLOT, REFLINE, GRID, AXES
%

% for Matlab R13
% version 1.0 (feb 2006)
% (c) Jos van der Geest
% email: jos@jasen.nl

error(nargchk(1,Inf,nargin)) ;

% check the arguments
if ~isnumeric(x),
    error('Numeric argument expected') ;
end