> type foo.py
from spacy import load
> type mypy.ini
[mypy]
strict = True
> mypy foo.py
Traceback (most recent call last):
  File "c:\Program Files\Python39\lib\runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "c:\Program Files\Python39\lib\runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "C:\Users\vito.detullio\Desktop\DELME\venv\Scripts\mypy.exe\__main__.py", line 7, in <module>
  File "c:\users\vito.detullio\desktop\delme\venv\lib\site-packages\mypy\__main__.py", line 11, in console_entry
    main(None, sys.stdout, sys.stderr)
  File "mypy\main.py", line 90, in main
  File "mypy\build.py", line 179, in build
  File "mypy\build.py", line 253, in _build
  File "mypy\build.py", line 2638, in dispatch
  File "mypy\build.py", line 2962, in process_graph
  File "mypy\build.py", line 3079, in process_stale_scc
  File "mypy\build.py", line 2251, in write_cache
  File "mypy\build.py", line 1461, in write_cache
  File "mypy\nodes.py", line 313, in serialize
  File "mypy\nodes.py", line 3140, in serialize
  File "mypy\nodes.py", line 3076, in serialize
AssertionError

> python --version
Python 3.9.1
> python -mpip freeze
blis==0.7.4
catalogue==2.0.4
certifi==2020.12.5
chardet==4.0.0
click==7.1.2
cymem==2.0.5
en-core-web-sm @ https://github.com/explosion/spacy-models/releases/download/en_core_web_sm-3.0.0/en_core_web_sm-3.0.0-py3-none-any.whl
idna==2.10
Jinja2==3.0.1
MarkupSafe==2.0.1
murmurhash==1.0.5
mypy==0.812
mypy-extensions==0.4.3
numpy==1.20.3
packaging==20.9
pathy==0.5.2
preshed==3.0.5
pydantic==1.7.4
pyparsing==2.4.7
requests==2.25.1
smart-open==3.0.0
spacy==3.0.6
spacy-legacy==3.0.5
srsly==2.4.1
thinc==8.0.3
tqdm==4.61.0
typed-ast==1.4.3
typer==0.3.2
typing-extensions==3.10.0.0
urllib3==1.26.5
wasabi==0.8.2