Switch to sys.version_info checks

src/test/test_events.py

@@ -1,4 +1,5 @@
 """Test the events manager and collections."""
+from __future__ import annotations
 from unittest.mock import create_autospec
 
 import pytest

src/utils.py

@@ -82,9 +82,9 @@
 copyreg.add_extension('srctools.keyvalues', 'Keyvalues', 246)
 
 lcm: Callable[[int, int], int]
-try:
+if sys.version_info >= (3, 9):
     from math import lcm
-except ImportError:
+else:
     def lcm(a: int, b: int) -> int:
         """Calculate the lowest common multiple.
 
@@ -93,9 +93,9 @@ def lcm(a: int, b: int) -> int:
         return (a * b) // math.gcd(a, b)
 
 
-try:
+if sys.version_info >= (3, 10):
     from contextlib import aclosing
-except ImportError:  # TODO Directly use stdlib when we drop 3.9 and below
+else:  # TODO Directly use stdlib when we drop 3.9 and below
     from async_generator import aclosing  # type: ignore  # noqa