raise RuntimeError when using unvalid input in kwant.continuum.sympify
I've just spent a whole day debugging a problem.
I used locals
on a sympy
input. Normally this should give a warning however when the function that calls something_hamiltonian(sympy_ham, locals=locals)
is nested deeply enough, the warning doesn't show up at all. Instead, I think we should raise an error to help the user.
Edited by Bas Nijholt