development dependencies needed for type stubs not used when target python version doesn't match that of development environments

[cjw296]

I'm developing my library in a Python 3.12 virtual environment, but I would like to target Python 3.11 as a minimum, so had python the following in my pytype.toml:

python_version = '3.11'

However, my project relies on django-stubs to be installed in order to be able to be successfully type checked.

When I have python_version set to 3.12, I do not get type checking errors for django.

However, when I have python_version set to 3.11 I get errors such as the following, suggesting that django-stubs is not being used:

$ pytype --config pytype.toml 
Computing dependencies
Analyzing 26 sources with 0 local dependencies
ninja: Entering directory `.pytype'
[3/35] check testfixtures.tests.test_django.models
FAILED: /Users/chris/vcs/git/testfixtures/.pytype/pyi/testfixtures/tests/test_django/models.pyi 
/Users/chris/virtualenvs/testfixtures_312/bin/python -m pytype.main --imports_info /Users/chris/vcs/git/testfixtures/.pytype/imports/testfixtures.tests.test_django.models.imports --module-name testfixtures.tests.test_django.models --platform darwin -V 3.11 -o /Users/chris/vcs/git/testfixtures/.pytype/pyi/testfixtures/tests/test_django/models.pyi --analyze-annotated --nofail --quick /Users/chris/vcs/git/testfixtures/testfixtures/tests/test_django/models.py
/Users/chris/vcs/git/testfixtures/testfixtures/tests/test_django/models.py:1:1: error: in <module>: Can't find module 'django.db'. [import-error]

How can I have pytype check for 3.11 when it requires dependencies such as these?