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_set_priors.m
    path of file: ./repos/ExploreASL/External/SPMmodified
    
    the code of the file until where you have to start completion: function [block] = spm_vb_set_priors(block,priors,vxyz)
% Set up precision parameters and optimisation options to correspond to priors
% FORMAT [block] = spm_vb_set_priors(block,priors,vxyz)
%
% block   - VB-GLM-AR data structure (see spm_vb_glmar)
% priors  - For regression coefficients:
%
%           .W= 'Spatial - UGL' : coeffs that are spatially regularised
%               'Spatial - GMRF' : as above but different spatial prior
%               'Spatial - LORETA' : as above but different spatial prior
%               'Spatial - WGL' : as above but different spatial prior
%               'Voxel - Shrinkage' : that are shrunk voxel-wise
%               'Voxel - Uninformative' : coeffs without prior
%
%           For AR coefficients:
%

    
function [block] = spm_vb_set_priors(block,priors,vxyz)
% Set up precision parameters and optimisation options to correspond to priors
% FORMAT [block] = spm_vb_set_priors(block,priors,vxyz)
%
% block   - VB-GLM-AR data structure (see spm_vb_glmar)
% priors  - For regression coefficients:
%
%           .W= 'Spatial - UGL' : coeffs that are spatially regularised
%               'Spatial - GMRF' : as above but different spatial prior
%               'Spatial - LORETA' : as above but different spatial prior
%               'Spatial - WGL' : as above but different spatial prior
%               'Voxel - Shrinkage' : that are shrunk voxel-wise
%               'Voxel - Uninformative' : coeffs without prior
%
%           For AR coefficients:
%
%           .A= 'Spatial - UGL' : coeffs that are spatially regularised
%               'Spatial - GMRF' : as above but different spatial prior
%               'Spatial - LORETA' : as above but different spatial prior
%               'Voxel - Shrinkage' : that are shrunk voxel-wise
%               'Voxel - Uninformative' : coeffs without prior
%               'Voxel - Limiting' : Voxel-specific coeffs as limiting case
%                                    of a LORETA prior
%               'block - Limiting' : block-specific coeffs as limiting case
%                                    of a LORETA prior
%               'Discrete' : Different coeffs as function of grey/white/CSF
%                            or other masks
%
% vxyz    - locations of voxels 
%__________________________________________________________________________
% Copyright (C) 2005-2014 Wellcome Trust Centre for Neuroimaging

% Will Penny and Lee Harrison
% $Id: spm_vb_set_priors.m 6079 2014-06-30 18:25:37Z spm $

if ~isfield(block,'verbose')
    block.verbose = 0;
end