From e6e69bac74eaaad650f478d9b7e4c19ae79ba78e Mon Sep 17 00:00:00 2001
From: Stefano Rivera <stefano@rivera.za.net>
Date: Sun, 27 Oct 2024 10:38:50 -0700
Subject: [PATCH] Restore support for Python 3.9

Fixes: #16
---
 README.md | 3 ++-
 plugin.py | 9 +++++----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index 5c0061d..7d301e8 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,8 @@ Currently supported:
 
 - Before installing, you need to have `python3` installed, with a
   working `venv` module.
-  - On Debian/Ubuntu/Raspbian, this means installing the `python3-venv` package.
+  - On Debian/Ubuntu/Raspberry Pi OS, this means installing the `python3-venv` package.
+  - Supported Python 3 versions: >= 3.9
 - Install this plugin through SignalK / npm.
 - Use the native Victron app to obtain advertisement keys for
   communicating with your Victron devices.
diff --git a/plugin.py b/plugin.py
index 5ae4784..1e3e51c 100644
--- a/plugin.py
+++ b/plugin.py
@@ -5,7 +5,7 @@
 import json
 import logging
 import sys
-from typing import Any, Callable, TypeAlias
+from typing import Any, Callable, Union
 
 from bleak.backends.device import BLEDevice
 from victron_ble.devices import (
@@ -26,8 +26,9 @@
 
 logger = logging.getLogger("signalk-victron-ble")
 
-SignalKDelta: TypeAlias = dict[str, list[dict[str, Any]]]
-SignalKDeltaValues: TypeAlias = list[dict[str, int | float | str | None]]
+# 3.9 compatible TypeAliases
+SignalKDelta = dict[str, list[dict[str, Any]]]
+SignalKDeltaValues = list[dict[str, Union[int, float, str, None]]]
 
 
 @dataclasses.dataclass
@@ -35,7 +36,7 @@ class ConfiguredDevice:
     id: str
     mac: str
     advertisement_key: str
-    secondary_battery: str | None
+    secondary_battery: Union[str, None]
 
 
 class SignalKScanner(Scanner):