def METHOD_NAME(self, dataset):
    result = drifter_meta()
    self.assertEqual(
        result,
        {
            "imei": {},
            "wmo": {},
            "deployment": {},
        },
    )
    dataset.return_value.__enter__.return_value.variables = {
        "buoy": ["abcd.nc"],
        "imei": [["IME"]],
        "wmo": [["WMO"]],
        "deployment": [["DEP"]],
    }
    with patch("utils.misc.chartostring", new=lambda x: x):
        result = drifter_meta()
    self.assertEqual(
        result,
        {
            "imei": {"IME": ["abcd"]},
            "wmo": {"WMO": ["abcd"]},
            "deployment": {"DEP": ["abcd"]},
        },
    )