def test_view_failed_delitem(attr):
    adata = gen_adata((10, 10))
    view = adata[5:7, :][:, :5]
    adata_hash = joblib.hash(adata)
    view_hash = joblib.hash(view)

    with pytest.raises(KeyError):
        getattr(view, attr).__delitem__("not a key")

    assert view.is_view
    assert adata_hash == joblib.hash(adata)
    assert view_hash == joblib.hash(view)
def _init_signals(self):
        """Initializes the backends and gtk signals """
        self.connect("cursor-changed", self.on_select_row)
        _signals = BackendSignals()
        _signals.connect(_signals.BACKEND_ADDED, self.on_backend_added)
        _signals.connect(_signals.BACKEND_STATE_TOGGLED,
                         self.on_backend_state_changed)