Stubgen giving error about self documenting expressions in f-strings #10791

Critical error during semantic analysis: path/to/script.py:140: error: f-string: self documenting expressions are only supported in Python 3.8 and greater

(venv) $ which python
/home/cquick/test/venv/bin/python
(venv) $ which mypy
/home/cquick/test/venv/bin/mypy
(venv) $ which stubgen
/home/cquick/test/venv/bin/stubgen

(venv) $ python -V
Python 3.9.6

(venv) $ python -m pip install -U mypy
Requirement already satisfied: mypy in ./venv/lib/python3.9/site-packages (0.910)
Requirement already satisfied: typing-extensions>=3.7.4 in ./venv/lib/python3.9/site-packages (from mypy) (3.10.0.0)
Requirement already satisfied: toml in ./venv/lib/python3.9/site-packages (from mypy) (0.10.2)
Requirement already satisfied: mypy-extensions<0.5.0,>=0.4.3 in ./venv/lib/python3.9/site-packages (from mypy) (0.4.3)

(venv) $ mypy -V
mypy 0.910

(venv) $ cat test.py
#!/usr/bin/env python3

def foo(x):
    print(f"{x = }")

if __name__ == "__main__":
    foo(1)

(venv) $ python test.py
x = 1

(venv) $ stubgen test.py
Critical error during semantic analysis: test.py:4: error: f-string: self documenting expressions are only supported in Python 3.8 and greater