def METHOD_NAME(self):
    assert len(self.cocktail) == sum(len(mol) * self.packmol_config[i]["number"] for i, mol in enumerate(self.mols))
    atoms = (
        self.ethanol_atoms * self.packmol_config[0]["number"] + self.water_atoms * self.packmol_config[1]["number"]
    )
    atoms_ans = [str(site.specie) for site in self.cocktail]
    assert atoms == atoms_ans