## TL;DR
Upgrade pytest to 8.x: `python -m pip install -U pytest`. The `_pytest.scope` module was added in pytest 8.0, so any plugin or tool importing it (like newer anyio) breaks on pytest 7.x and older with this exact error.

```text
ModuleNotFoundError: No module named '_pytest.scope'
```

## Fix it

1. **Check your pytest version.** Run `pytest --version` or `python -m pip show pytest`.
   - Expected: you will see pytest 7.x or older.

2. **Upgrade pytest.** Run `python -m pip install -U pytest`.
   - Expected: `Successfully installed pytest-8.x.x`.

3. **Re-run your tests.** The importing plugin (often anyio's pytest plugin) should now load cleanly.
   - Expected: no ModuleNotFoundError, tests collect normally.

4. **If you cannot upgrade pytest**, pin the plugin to a version that supports your pytest. For anyio, that means staying on anyio 3.x with pytest 7.x.

## When this applies
- The traceback shows a plugin (anyio, or similar) doing `from _pytest.scope import ...` or `import _pytest.scope`.
- You recently upgraded a pytest plugin but not pytest itself.

## When it does not apply
- If the missing module is `pytest` itself (not `_pytest.scope`), pytest is simply not installed.
- If the error names a hook (like `pytest_namespace`), that is a plugin validation error, a different problem.

## Tool compatibility
pytest 8.0+ provides `_pytest.scope`. anyio 4.x requires it. Python 3.8+.

## Why it happens
`_pytest.scope` is an internal pytest module introduced in pytest 8.0. Plugins written against pytest 8 import it at load time. If your environment pins pytest 7.x (common in CI images or libraries with upper bounds), the import fails even though everything else works.

## Edge cases
- Some distributions pin pytest via constraints files; check `pip freeze | grep -i pytest` and any constraints files.
- If you must stay on pytest 7, downgrade the plugin instead: `pip install "anyio<4"`.