diff --git a/vault_oidc_ssh_cert_action.py b/vault_oidc_ssh_cert_action.py
index ad196bc..f3af718 100644
--- a/vault_oidc_ssh_cert_action.py
+++ b/vault_oidc_ssh_cert_action.py
@@ -1,6 +1,7 @@
 import os
 import subprocess
 import tempfile
+from typing import Tuple
 from urllib.parse import urlparse
 
 import requests
@@ -106,7 +107,7 @@ def _issue_ssh_cert(
 
 def _generate_and_sign(
     vault_server: str, vault_token: str, ssh_backend: str, ssh_role: str
-) -> tuple[str, str]:
+) -> Tuple[str, str]:
     key_fname = "id_github"
     cert_fname = f"{key_fname}-cert.pub"