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: WNDistribution.m
    path of file: ./repos/libDirectional/lib/distributions/Hypertorus/Circle
    
    the code of the file until where you have to start completion: classdef WNDistribution < AbstractCircularDistribution
    % wrapped normal distribution
    %
    % see Sreenivasa Rao Jammalamadaka and A. SenGupta, "Topics in Circular
    % Statistics", 2001, Sec. 2.2.6, page 44f.
    

    
function wn = shift(this, angle)
            % Shift distribution by the given angle
            %
            % Parameters:
            %   shiftAngles (scalar)
            %       angle to shift by
            % Returns:
            %   wn (WNDistribution)
            %       shifted distribution
            assert(isscalar (angle));
            wn = WNDistribution(this.mu+angle,this.sigma); % Mod is done in constructor
        end