def update_mol(mol):
    """
    Update atom types, multiplicity, and atom charges in the molecule.

    Args:
        mol (Molecule): The molecule to update.

    Returns:
        Molecule: the updated molecule.
    """
    for atom in mol.atoms:
        atom.update_charge()
    mol.update_atomtypes(log_species=False, raise_exception=False)
    mol.update_multiplicity()
    mol.identify_ring_membership()
    return mol