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: conv.m
    path of file: ./repos/d2d/arFramework3/ThirdParty/StrucID/adimat/arrderivclass/@arrdercont
    
    the code of the file until where you have to start completion: % function obj = conv(a, b, shape)
%
% This file is part of the ADiMat runtime environment

    
function obj = conv(a, b, shape)
%
% This file is part of the ADiMat runtime environment
%
% Copyright (c) 2018 Johannes Willkomm
%
function obj = conv(a, b, shape)
  if nargin < 3
    shape = 'full';
  end