Couldn't load_learner in windows

In colab, I trained a model and it works well

from google.colab import drive
drive.mount('/content/gdrive')
!pip install fastai --upgrade
from fastai.tabular.all import *
from fastai import __version__
print(__version__)
learn = load_learner(fname='/content/gdrive/My Drive/mymodel',cpu=False)
learn

Mounted at /content/gdrive
Collecting fastai
Successfully installed fastai-2.4 fastcore-1.3.20
2.4
<fastai.tabular.learner.TabularLearner at 0x7f87523a1ed0>

However, I failed in loading it in Windows:

Python 3.8.5 (default, Sep  3 2020, 21:29:08) [MSC v.1916 64 bit (AMD64)] :: Anaconda, Inc. on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from fastai import __version__
>>> __version__
'2.4'
>>> from fastai.learner import *
>>> load_learner(fname='./mymodel')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "D:\program\anaconda3\envs\sl3\lib\site-packages\fastai\learner.py", line 384, in load_learner
    res = torch.load(fname, map_location='cpu' if cpu else None, pickle_module=pickle_module)
  File "D:\program\anaconda3\envs\sl3\lib\site-packages\torch\serialization.py", line 594, in load
    return _load(opened_zipfile, map_location, pickle_module, **pickle_load_args)
  File "D:\program\anaconda3\envs\sl3\lib\site-packages\torch\serialization.py", line 853, in _load
    result = unpickler.load()
  File "D:\program\anaconda3\envs\sl3\lib\pathlib.py", line 1040, in __new__
    raise NotImplementedError("cannot instantiate %r on your system"
NotImplementedError: cannot instantiate 'PosixPath' on your system

What did I miss?