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: basis_col.m
    path of file: ./repos/fieldtrip/external/afni
    
    the code of the file until where you have to start completion: function basis = basis_col(A)
%
% Bases
% 
% basis_col(A) produces a basis for the subspace of Eucldiean n-space 
% spanned by the vectors {u1,u2,...}, where the matrix A is formed from 
% these vectors as its columns. That is, the subspace is the column space 
% of A. The columns of the matrix that is returned are the basis vectors 
% for the subspace. These basis vectors will be a subset of the original 
% vectors. An error is returned if a basis for the zero vector space is 
% attempted to be produced.
%
% For example, if the vector space V = span{u1,u2,...}, where u1,u2,... are
% row vectors, then set A to be [u1' u2' ...].
%
% For example, if the vector space V = Col(B), where B is an m x n matrix,
% then set A to be equal to B.
%
%  Function written by Anthony Russo, downloaded from MatlabCentral.
%

matrix_size = size(A);

m = matrix_size(1,1);
n = matrix_size(1,2);

if A == zeros(m,n)
    error('There does not exist a basis for the zero vector space.');
elseif n == 1
    basis = A;
else
    flag = 0;

    if n == 2
        multiple = A(1,2)/A(1,1);

    
function basis = basis_col(A)
%
% Bases
% 
% basis_col(A) produces a basis for the subspace of Eucldiean n-space 
% spanned by the vectors {u1,u2,...}, where the matrix A is formed from 
% these vectors as its columns. That is, the subspace is the column space 
% of A. The columns of the matrix that is returned are the basis vectors 
% for the subspace. These basis vectors will be a subset of the original 
% vectors. An error is returned if a basis for the zero vector space is 
% attempted to be produced.
%
% For example, if the vector space V = span{u1,u2,...}, where u1,u2,... are
% row vectors, then set A to be [u1' u2' ...].
%
% For example, if the vector space V = Col(B), where B is an m x n matrix,
% then set A to be equal to B.
%
%  Function written by Anthony Russo, downloaded from MatlabCentral.
%

matrix_size = size(A);

m = matrix_size(1,1);
n = matrix_size(1,2);

if A == zeros(m,n)
    error('There does not exist a basis for the zero vector space.');
elseif n == 1
    basis = A;
else
    flag = 0;

    if n == 2
        multiple = A(1,2)/A(1,1);
        count = 0;
 
        for i = 1:m
            if A(i,2)/A(i,1) == multiple
                count = count + 1;
            end