docs: def unscale_dict(C):
      """Undo the scaling applied in `scale_dict`."""
      C_out = {k: _scale_dict[k] * v for k, v in C.items()}
      for k in C_symm_keys[8]:
          C_out['qqql'] = unscale_8(C_out['qqql'])
      return C_out