diff --git a/chatmastermind/configuration.py b/chatmastermind/configuration.py
index bc58574..9cb7885 100644
--- a/chatmastermind/configuration.py
+++ b/chatmastermind/configuration.py
@@ -1,5 +1,5 @@
 import pathlib
-from typing import TypedDict, Any
+from typing import TypedDict, Any, Union
 
 
 class OpenAIConfig(TypedDict):
@@ -15,7 +15,7 @@ class OpenAIConfig(TypedDict):
     presence_penalty: float
 
 
-def openai_config_valid(conf: dict[str, str | float | int]) -> bool:
+def openai_config_valid(conf: dict[str, Union[str, float, int]]) -> bool:
     """
     Checks if the given Open AI configuration dict is complete
     and contains valid types and values.