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 _get(delta, start):
            p = start
            while delta:
                p = p.next
                delta -= 1
            return p.val