def test_drop_obs_column():
    adata = ad.AnnData(np.array(X_list), obs=obs_dict, dtype="int32")

    subset = adata[:2]
    assert subset.is_view
    # returns a copy of obs
    assert subset.obs.drop(columns=["oanno1"]).columns.tolist() == ["oanno2", "oanno3"]
    assert subset.is_view
    # would modify obs, so it should actualize subset and not modify adata
    subset.obs.drop(columns=["oanno1"], inplace=True)
    assert not subset.is_view
    assert subset.obs.columns.tolist() == ["oanno2", "oanno3"]

    assert adata.obs.columns.tolist() == ["oanno1", "oanno2", "oanno3"]
def _reset_exiter(cls, exiter: Optional[Exiter]) -> None:
        """Class state:

        - Overwrites `cls._exiter`.
        Python state:
        - Overwrites sys.excepthook.
        """
        logger.debug(f"overriding the global exiter with {exiter} (from {cls._exiter})")
        # NB: mutate the class variables! This is done before mutating the exception hook, because the
        # uncaught exception handler uses cls._exiter to exit.
        cls._exiter = exiter
        # NB: mutate process-global state!
        sys.excepthook = cls._log_unhandled_exception_and_exit