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: MALAOptions.m
    path of file: ./repos/PESTO/@MALAOptions
    
    the code of the file until where you have to start completion: classdef MALAOptions < matlab.mixin.CustomDisplay
   % MALAOptions provides an option container to pass options as subclass
   % 
    
function this = set.regFactor(this, value)
         if(isnumeric(value) && value > 0)
            this.regFactor = lower(value);
         else
            error(['Please specify a positive regularization factor for ill conditioned covariance'...
                ' matrices of the adapted proposal density, e.g. ' ...
                'PestoSamplingOptions.MALA.regFactor = 1e-5']);
         end