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: PanelPropString.m
    path of file: ./repos/BRAPH-2/braph2/src/gui
    
    the code of the file until where you have to start completion: classdef PanelPropString < PanelProp
	%PanelPropString plots the panel of a property string.
	% It is a subclass of <a href="matlab:help PanelProp">PanelProp</a>.
	%
	% A String Prop Panel (PanelPropString) plots the panel for a STRING property with an edit field.
	% It works for all categories.
	%
	% The list of PanelPropString properties is:
	%  <strong>1</strong> <strong>ELCLASS</strong> 	ELCLASS (
    
function check_out = existsProp(prop)
			%EXISTSPROP checks whether property exists in string prop panel/error.
			%
			% CHECK = PanelPropString.EXISTSPROP(PROP) checks whether the property PROP exists.
			%
			% Alternative forms to call this method are:
			%  CHECK = PR.EXISTSPROP(PROP) checks whether PROP exists for PR.
			%  CHECK = Element.EXISTSPROP(PR, PROP) checks whether PROP exists for PR.
			%  CHECK = Element.EXISTSPROP(PanelPropString, PROP) checks whether PROP exists for PanelPropString.
			%
			% Element.EXISTSPROP(PROP) throws an error if the PROP does NOT exist.
			%  Error id: [BRAPH2:PanelPropString:WrongInput]
			%
			% Alternative forms to call this method are:
			%  PR.EXISTSPROP(PROP) throws error if PROP does NOT exist for PR.
			%   Error id: [BRAPH2:PanelPropString:WrongInput]
			%  Element.EXISTSPROP(PR, PROP) throws error if PROP does NOT exist for PR.
			%   Error id: [BRAPH2:PanelPropString:WrongInput]
			%  Element.EXISTSPROP(PanelPropString, PROP) throws error if PROP does NOT exist for PanelPropString.
			%   Error id: [BRAPH2:PanelPropString:WrongInput]
			%
			% Note that the Element.EXISTSPROP(PR) and Element.EXISTSPROP('PanelPropString')
			%  are less computationally efficient.
			%
			% See also getProps, existsTag.
			
			check = prop >= 1 && prop <= 37 && round(prop) == prop; %CET: Computational Efficiency Trick
			
			if nargout == 1
				check_out = check;
			elseif ~check
				error( ...
					['BRAPH2' ':PanelPropString:' 'WrongInput'], ...
					['BRAPH2' ':PanelPropString:' 'WrongInput' '\n' ...
					'The value ' tostring(prop, 100, ' ...') ' is not a valid prop for PanelPropString.'] ...
					)
			end