Update packages/google-auth/google/auth/_default.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: daniel-sanche

packages/google-auth/google/auth/_default.py

@@ -591,7 +591,7 @@ def _apply_quota_project_id(credentials, quota_project_id):
 
 
 def default(
-    scopes: Optional[Sequence[str] | str] = None,
+    scopes: Optional[Union[Sequence[str], str]] = None,
     request: Optional["google.auth.transport.Request"] = None,
     quota_project_id: Optional[str] = None,
     default_scopes: Optional[Sequence[str]] = None,