def METHOD_NAME(cls):
    co_species = ["C", "O"]
    co_coords = [[0.0, 0.0, 0.0], [1.3, 0.0, 0.0]]
    cls.co_mol = Molecule(co_species, co_coords)
    cls.co_opt_ref_in = QCInput.from_file(
        os.path.join(module_dir, "..", "..", "test_files", "co_qc.in")
    )
    cls.co_opt_diff_in = QCInput.from_file(
        os.path.join(module_dir, "..", "..", "test_files", "co_qc_diff.in")
    )
    cls.opt_mol_ref_in = QCInput.from_file(
        os.path.join(module_dir, "..", "..", "test_files", "to_opt.qin")
    )
    cls.opt_mol = cls.opt_mol_ref_in.molecule
    cls.opt_mol_pcm_ref_in = QCInput.from_file(
        os.path.join(module_dir, "..", "..", "test_files", "to_opt_pcm.qin")
    )
    cls.opt_mol_smd_ref_in = QCInput.from_file(
        os.path.join(module_dir, "..", "..", "test_files", "to_opt_smd.qin")
    )
    cls.v5_ref_in = QCInput.from_file(
        os.path.join(module_dir, "..", "..", "test_files", "v5.qin")
    )
    cls.v6_ref_in = QCInput.from_file(
        os.path.join(module_dir, "..", "..", "test_files", "v6.qin")
    )