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 __exit__(self, exc_type, exc_value, traceback):
        connection = get_connection(self.using)
        try:
            self._no_monkey.__exit__(self, exc_type, exc_value, traceback)
        except DatabaseError:
            transaction_states[self.using].rollback()
        else:
            if not connection.closed_in_transaction and exc_type is None and \
                    not connection.needs_rollback:
                if transaction_states[self.using]:
                    transaction_states[self.using].commit()
            else:
                transaction_states[self.using].rollback()