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 clear(self):
    for unused_ in range(len(self._items)):
      self.remove_item(self._items[0])