[Kwant] Getting the List of Neighbors After finalization

[Henry Axt]

I am attempting to approximate the first derivate over the system's 
wavefunction values, yet it seems there is no neighbors() function to call 
after finalization of the system.
What would be the method to attain a list of neighboring sites after 
finalizaion? Is the ordering of the sites preserved before and after 
finalization?