diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 66ef2e2..287df15 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -9,12 +9,12 @@ ci:
 
 repos:
   - repo: https://github.com/commitizen-tools/commitizen
-    rev: v4.16.5
+    rev: v4.19.0
     hooks:
       - id: commitizen
         stages: [commit-msg]
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v5.0.0
+    rev: v6.0.0
     hooks:
       - id: debug-statements
       - id: check-builtin-literals
@@ -28,11 +28,11 @@ repos:
       - id: end-of-file-fixer
       - id: trailing-whitespace
   - repo: https://github.com/tox-dev/pyproject-fmt
-    rev: "v2.25.3"
+    rev: "v2.29.4"
     hooks:
       - id: pyproject-fmt
   - repo: https://github.com/python-poetry/poetry
-    rev: 2.4.1
+    rev: 2.5.1
     hooks:
       - id: poetry-check
   - repo: https://github.com/pre-commit/mirrors-prettier
@@ -41,7 +41,7 @@ repos:
       - id: prettier
         args: ["--tab-width", "2"]
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.9.10
+    rev: v0.16.9
     hooks:
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix, --unsafe-fixes]
@@ -52,7 +52,7 @@ repos:
       - id: codespell
         args: [-L, astroid]
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.20.2
+    rev: v2.3.1
     hooks:
       - id: mypy
         additional_dependencies: [types-pyyaml, strenum]
diff --git a/README.md b/README.md
index 185bbf7..7be502e 100644
--- a/README.md
+++ b/README.md
@@ -72,7 +72,11 @@ $ account-codes-jp list --type blue-return
 ```
 
 ```python
-from account_codes_jp import get_blue_return_accounts, get_account_type_factory, AccountType
+from account_codes_jp import (
+    get_blue_return_accounts,
+    get_account_type_factory,
+    AccountType,
+)
 
 G = get_blue_return_accounts()
 t = get_account_type_factory(G)
diff --git a/src/account_codes_jp/_blue_return.py b/src/account_codes_jp/_blue_return.py
index 2d977eb..1724791 100644
--- a/src/account_codes_jp/_blue_return.py
+++ b/src/account_codes_jp/_blue_return.py
@@ -38,7 +38,7 @@ def from_nested_dict(
             if isinstance(grandchildren, Mapping):
                 q.append((id_child, grandchildren))
             elif isinstance(grandchildren, list):
-                q.append((id_child, {k: None for k in grandchildren}))
+                q.append((id_child, dict.fromkeys(grandchildren)))
     return G
 
 
diff --git a/tests/test_dunder_main.py b/tests/test_dunder_main.py
index 843c490..1979168 100644
--- a/tests/test_dunder_main.py
+++ b/tests/test_dunder_main.py
@@ -4,7 +4,7 @@
 
 def test_can_run_as_python_module():
     """Run the CLI as a Python module."""
-    result = subprocess.run(  # noqa: S603
+    result = subprocess.run(
         [sys.executable, "-m", "account_codes_jp", "--help"],
         check=True,
         capture_output=True,