noxfile causes mypy error

[epenet]

When mypy is set to warn on unreachable code, then upgrading nox from 2020.12.31 to 2021.6.12 causes a "Statement is unreachable" error on line 47

noxfile.py: note: In function "activate_virtualenv_in_precommit_hooks":
noxfile.py:47:9: error: Statement is unreachable  [unreachable]
            return

These are the culprit lines:

cookiecutter-hypermodern-python/{{cookiecutter.project_name}}/noxfile.py

Lines 46 to 47 in 735cf23

	if session.bin is None:
	return

This is my mypy.ini:

[mypy]
check_untyped_defs = True
disallow_any_generics = True
disallow_incomplete_defs = True
disallow_subclassing_any = True
disallow_untyped_calls = True
disallow_untyped_decorators = True
disallow_untyped_defs = True
no_implicit_optional = True
no_implicit_reexport = True
pretty = True
show_column_numbers = True
show_error_codes = True
show_error_context = True
strict_equality = True
warn_redundant_casts = True
warn_return_any = True
warn_unreachable = True
warn_unused_configs = True
warn_unused_ignores = True

[epenet]

I have (temporarily) added #type: ignore the line on my project: hacf-fr/renault-api#310

[cjolowicz]

Right, session.bin used to be Optional in Nox, this was fixed in wntrblm/nox#378. So the two lines should now be removed.