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: GlobalEfficiencyAv.m
    path of file: ./repos/BRAPH-2/braph2/measures
    
    the code of the file until where you have to start completion: classdef GlobalEfficiencyAv < GlobalEfficiency
	%GlobalEfficiencyAv is the graph Average Global Efficiency.
	% It is a subclass of <a href="matlab:help GlobalEfficiency">GlobalEfficiency</a>.
	%
	% The Average Global Efficiency (GlobalEfficiencyAv) is the average of the 
	% global efficiency within each layer.
	%
	% The list of GlobalEfficiencyAv properties is:
	%  <st
    
function prop_number = getPropNumber(varargin)
			%GETPROPNUMBER returns the property number of average global efficiency.
			%
			% N = GlobalEfficiencyAv.GETPROPNUMBER() returns the property number of average global efficiency.
			%
			% N = GlobalEfficiencyAv.GETPROPNUMBER(CATEGORY) returns the property number of average global efficiency
			%  of category CATEGORY
			%
			% Alternative forms to call this method are:
			%  N = M.GETPROPNUMBER([CATEGORY]) returns the property number of the average global efficiency M.
			%  N = Element.GETPROPNUMBER(M) returns the property number of 'M'.
			%  N = Element.GETPROPNUMBER('GlobalEfficiencyAv') returns the property number of 'GlobalEfficiencyAv'.
			%
			% Note that the Element.GETPROPNUMBER(M) and Element.GETPROPNUMBER('GlobalEfficiencyAv')
			%  are less computationally efficient.
			%
			% See also getProps, Category.
			
			%CET: Computational Efficiency Trick
			
			if nargin == 0
				prop_number = 15;
				return
			end