def METHOD_NAME(self, dataset):
    """
    Converts .tar.gz to a .db file
    """
    if self.raw_path is None or not os.path.exists(self.raw_path):
        # TODO: can we download here automatically like QM9?
        raise AtomsDataModuleError(
            "The path to the raw dataset is not provided or invalid and the db-file does "
            "not exist!"
        )
    logging.info("Converting %s to a .db file.." % self.raw_path)
    tar = tarfile.open(self.raw_path, "r:gz")
    names = tar.getnames()
    tar.extractall()
    tar.close()
    structures = read("structures.xyz", index=":")
    Y = np.loadtxt("bandgaps.csv")
    [os.remove(name) for name in names]
    atoms_list = []
    property_list = []
    for i, at in enumerate(structures):
        atoms_list.append(at)
        property_list.append({OrganicMaterialsDatabase.BandGap: np.array([Y[i]])})
    dataset.add_systems(atoms_list=atoms_list, property_list=property_list)