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: spm_vb_roi_anova.m
    path of file: ./repos/spm
    
    the code of the file until where you have to start completion: function [post,model] = spm_vb_roi_anova (VOI_fname,SPM,factor)
% Bayesian ANOVA for a region of interest
% FORMAT [post,model] = spm_vb_roi_anova (VOI_fname,SPM,factor)
%
% VOI_fname   - VOI filename

    
function [post,model] = spm_vb_roi_anova (VOI_fname,SPM,factor)
% Bayesian ANOVA for a region of interest
% FORMAT [post,model] = spm_vb_roi_anova (VOI_fname,SPM,factor)
%
% VOI_fname   - VOI filename
% SPM         - SPM data structure
% factor      - data structure relating conditions to levels of factors
%
% model       - data structure describing models
%               (m).F             model evidence
%               (m).X             design matrix
% post        - Posterior probabilities of
%               .factor1        main effect of factor 1
%               .factor2        main effect of factor 2
%               .interaction    interaction
%               .average        average
%__________________________________________________________________________

% Will Penny 
% Copyright (C) 2005-2022 Wellcome Centre for Human Neuroimaging  


if nargin < 2
    [Pf, sts] = spm_select(1,'^SPM\.mat$','Select SPM.mat');
    if ~sts, return; end