def adata():
    adata = ad.AnnData(np.zeros((100, 100)))
    adata.obsm["o"] = np.zeros((100, 50))
    adata.varm["o"] = np.zeros((100, 50))
    return adata
def add_item(self, item):
    self._vbox_items.pack_start(item.widget, expand=False, fill=False)