Deploy the Pretrained Model on Raspberry Pi ERROR

When I run this demo in https://tvm.apache.org/docs/tutorials/frontend/deploy_model_on_rasp.html

there is a problem.

tvm/python/tvm/_ffi/runtime_ctypes.py", line 102, in __init__
    raise ValueError("Do not know how to handle type %s" % type_str)
ValueError: Do not know how to handle type object

How to solve it?