do not use | for Union yet

diff --git a/dns/btreezone.py b/dns/btreezone.py
index 6328577b0db9f9f035ad6a85dbaf55f07214e812..afd3005d9a5c7095a10d62a043818ae269ebf020 100644 (file)
--- a/dns/btreezone.py
+++ b/dns/btreezone.py
@@ -13,7 +13,7 @@
 
 import enum
 from dataclasses import dataclass
-from typing import Callable, MutableMapping, Optional, Tuple, cast
+from typing import Callable, MutableMapping, Optional, Tuple, Union, cast
 
 import dns.btree
 import dns.immutable
@@ -286,7 +286,7 @@ class ImmutableVersion(dns.zone.Version):
         self.delegations = version.delegations
         self.delegations.make_immutable()
 
-    def bounds(self, name: dns.name.Name | str) -> Bounds:
+    def bounds(self, name: Union[dns.name.Name, str]) -> Bounds:
         """Return the 'bounds' of *name* in its zone.
 
         The bounds information is useful when making an authoritative response, as