diff --git a/comicfn2dict/parse.py b/comicfn2dict/parse.py
index 0cca5af..c833a8d 100644
--- a/comicfn2dict/parse.py
+++ b/comicfn2dict/parse.py
@@ -1,4 +1,6 @@
 """Parse comic book archive names using the simple 'parse' parser."""
+from __future__ import annotations
+
 from calendar import month_abbr
 from copy import copy
 from pathlib import Path
diff --git a/comicfn2dict/unparse.py b/comicfn2dict/unparse.py
index 2b454b1..c4df994 100644
--- a/comicfn2dict/unparse.py
+++ b/comicfn2dict/unparse.py
@@ -1,4 +1,6 @@
 """Unparse comic filenames."""
+from __future__ import annotations
+
 from calendar import month_abbr
 from collections.abc import Callable, Mapping, Sequence
 from contextlib import suppress
diff --git a/poetry.lock b/poetry.lock
index 2e7e045..54240d9 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -963,5 +963,5 @@ test = ["pytest (>=6.0.0)", "setuptools (>=65)"]
 
 [metadata]
 lock-version = "2.0"
-python-versions = "^3.10"
-content-hash = "ad7bc225fd2048867bce6d5b96c739554d4b7a16bd035a60e4d7d2d82ecd7811"
+python-versions = "^3.9"
+content-hash = "39af5e6f01d257e457a710d8b126cbc467e520d7e2ad5942d3610fb503d5ce3a"
diff --git a/pyproject.toml b/pyproject.toml
index f716e85..7d29339 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -28,7 +28,7 @@ exclude = ["*/**/*~"]
 include = []
 
 [tool.poetry.dependencies]
-python = "^3.10"
+python = "^3.9"
 
 [tool.poetry.group.dev.dependencies]
 neovim = "^0.3.1"