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 _scale_vars(s, v_list):
  """Scale all variables in v_list by s."""
  return [s * v for v in v_list]