Bug in HF embedding code

[chmwzc]

Bug discovered while working with my Dec 2023 RAP attachment students. The following code throws an AssertionError:

from qibochem.driver import Molecule
from qibochem.ansatz import hf_circuit

# Molecule
mol = Molecule(xyz_file="../lih.xyz")
mol.run_pyscf()

mol.hf_embedding(frozen=[0, ])

I should have the fix already, but want to wait for #72 to be merged first.

[damarkian]

Thanks @chmwzc . I have merged #72 so please proceed.