diff --git a/src/idaes_flowsheet_processor/_testing/plugins.py b/src/idaes_flowsheet_processor/_testing/plugins.py
index be66b51..a51575d 100644
--- a/src/idaes_flowsheet_processor/_testing/plugins.py
+++ b/src/idaes_flowsheet_processor/_testing/plugins.py
@@ -1,3 +1,4 @@
+from __future__ import annotations  # allows using A | B for Python < 3.10
 import importlib
 from collections.abc import Iterable
 from collections.abc import Mapping
@@ -5,7 +6,11 @@
 from importlib.metadata import EntryPoint
 from pathlib import Path
 from types import ModuleType
-from typing import TypeAlias
+
+try:
+    from typing import TypeAlias
+except ImportError:
+    TypeAlias = type
 
 import pytest