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: aibhist.m
    path of file: ./repos/2015_Face_Detection/vlfeat/toolbox/noprefix
    
    the code of the file until where you have to start completion: function varargout = aibhist(varargin)
% VL_AIBHIST  Compute histogram over VL_AIB tree
%  H = VL_AIBHIST(PARENTS, DATA) computes the histogram of the data
%  points DATA on the VL_AIB tree defined by PARENTS. Each element of
%  DATA indexes one of the leaves of the VL_AIB tree.
%

    
function varargout = aibhist(varargin)
% VL_AIBHIST  Compute histogram over VL_AIB tree
%  H = VL_AIBHIST(PARENTS, DATA) computes the histogram of the data
%  points DATA on the VL_AIB tree defined by PARENTS. Each element of
%  DATA indexes one of the leaves of the VL_AIB tree.
%
%  H = VL_AIBHIST(PARENTS, DATA, 'HIST') treats DATA as an histograms.
%  In this case each compoment of DATA is the number of occurences of
%  the VL_AIB leaves corresponding to that component.
%
%  H has the same dimension of parents and counts how many data points
%  are descend