diff --git a/pyproject.toml b/pyproject.toml
index 8c34d49..0e231e2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,6 +15,14 @@ authors = [
     {name = "Pangeo developers", email = "ryan.abernathey@gmail.com"},
 ]
 requires-python = ">=3.8"
+classifiers = [
+  "Programming Language :: Python :: 3 :: Only",
+  "Programming Language :: Python :: 3.8",
+  "Programming Language :: Python :: 3.9",
+  "Programming Language :: Python :: 3.10",
+  "Programming Language :: Python :: 3.11",
+  "Programming Language :: Python :: 3.12",
+]
 dynamic = [
   "version",
 ]
diff --git a/rechunker/__init__.py b/rechunker/__init__.py
index a006adb..dbc5c71 100644
--- a/rechunker/__init__.py
+++ b/rechunker/__init__.py
@@ -1,4 +1,5 @@
 """Top-level package for Zarr Rechunker."""
+
 try:
     from ._version import __version__  # type: ignore
 except ImportError:
diff --git a/rechunker/algorithm.py b/rechunker/algorithm.py
index ae2c327..70f8d9f 100644
--- a/rechunker/algorithm.py
+++ b/rechunker/algorithm.py
@@ -1,4 +1,5 @@
 """Core rechunking algorithm stuff."""
+
 import logging
 import warnings
 from math import ceil, floor, prod
diff --git a/rechunker/api.py b/rechunker/api.py
index 0b3ced7..a0a350b 100644
--- a/rechunker/api.py
+++ b/rechunker/api.py
@@ -1,4 +1,5 @@
 """User-facing functions."""
+
 import html
 import textwrap
 from collections import defaultdict
diff --git a/rechunker/types.py b/rechunker/types.py
index e1ef210..0fdaa1c 100644
--- a/rechunker/types.py
+++ b/rechunker/types.py
@@ -1,4 +1,5 @@
 """Types definitions used by executors."""
+
 from dataclasses import dataclass
 from typing import (
     Any,