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: MARS_qromb2D.m
    path of file: ./repos/CBIG/external_packages/SD/SDv1.5.1-svn593/BasicTools
    
    the code of the file until where you have to start completion: % Contact ythomas@csail.mit.edu or msabuncu@csail.mit.edu for bugs or questions 
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%=========================================================================
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%  Copyright (c) 2008 Thomas Yeo and Mert Sabuncu
%  All rights reserved.
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%
    
function value = MARS_qromb2D(functor, x_limit_functor, ymin, ymax, varargin)

% 2D integrator
% Assumes integrating over region given by ymin-ymax and the horizontal
% extent is given by x_limit_functor(y) which gives back two extremal
% values.
% 
% Assumes functor is of the form functor(x, y, varargin)
% Assumes x_limit_functor is of the form [xmin, xmax] =
% x_limit_functor(y)

value = MARS_qromb(@functor2, ymin, ymax, x_limit_functor, functor, varargin{1:end