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: S2KernelHandle.m
    path of file: ./repos/mtex/S2Fun/S2KernelFunctions
    
    the code of the file until where you have to start completion: classdef S2KernelHandle < S2Kernel
  % defines a kernel function as a function of the rotational angle
  
  p
    
function as a function of the rotational angle
  
  properties
    fun = @(x) 1;
  end
      
  methods
    
    function psi = S2KernelHandle(fun,varargin)
      
      % extract parameter and halfwidth
      if nargin == 0, return;end