For any matrix A when we type
A.kernel()
 It returns
 A.kernel()
Free module of degree 45 and rank 12 over Integer Ring
Echelon basis matrix:`[ 1  0 -1][ 0  1  2][ 0  0  0]`
 How to I access this Echelon basis matrix directly?
I have tried this
A.kernel.echelon_form()
 but it says
TypeError: echelon_form() takes at least 2 arguments (1 given)