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: realpts.m
    path of file: ./repos/malini/Codes/deconvolution - model/spm8/marsbar-0.44/@maroi
    
    the code of the file until where you have to start completion: function [pts, vals] = realpts(o,sp)
% realpts method - returns 3xN XYZ matrix in mm

    
function [pts, vals] = realpts(o,sp)
% realpts method - returns 3xN XYZ matrix in mm
%
% $Id$

if nargin < 2
  error('Need space definition to find voxels');
end