diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index d42f18d0..03854829 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -78,6 +78,14 @@ repos:
   rev: v1.11.0
   hooks:
   - id: zizmor
+- repo: https://github.com/RobertCraigie/pyright-python
+  rev: v1.1.403
+  hooks:
+  - id: pyright
+    exclude: ^(docs|tests)/.*
+    additional_dependencies:
+    - pytest
+    - nodeenv
 ci:
   skip:
   - actionlint-docker
diff --git a/pytest_asyncio/plugin.py b/pytest_asyncio/plugin.py
index 9bfcfc64..5955bb0a 100644
--- a/pytest_asyncio/plugin.py
+++ b/pytest_asyncio/plugin.py
@@ -392,6 +392,7 @@ def _from_function(cls, function: Function, /) -> Function:
         Function item.
         """
         assert function.get_closest_marker("asyncio")
+        assert function.parent is not None
         subclass_instance = cls.from_parent(
             function.parent,
             name=function.name,