chore: improve type hinting

Author: farrokhi

dnsdiag/shared.py

@@ -27,6 +27,7 @@
 import random
 import string
 import sys
+from typing import Optional
 
 __version__ = '2.9.3'
 
@@ -46,7 +47,7 @@ def err(s: str) -> None:
     print(s, file=sys.stderr, flush=True)
 
 
-def set_protocol_exclusive(new_proto: int, current_option: str, proto_option_set: str | None) -> tuple[int, str]:
+def set_protocol_exclusive(new_proto: int, current_option: str, proto_option_set: Optional[str]) -> tuple[int, str]:
     """
     Set protocol ensuring mutual exclusivity.
 

dnseval.py

@@ -221,7 +221,7 @@ def main() -> None:
     verbose = False
     color_mode = False
     warmup = True
-    proto_option_set: str | None = None
+    proto_option_set: Optional[str] = None
     qname = 'wikipedia.org'
 
     try:

dnsping.py

@@ -188,7 +188,7 @@ def main() -> None:
     af = None
     af_ipv4_set = False
     af_ipv6_set = False
-    proto_option_set: str | None = None
+    proto_option_set: Optional[str] = None
     qname = 'wikipedia.org'
 
     try:

dnstraceroute.py

@@ -198,7 +198,7 @@ def main() -> None:
     af = None  # auto-detect from server address
     af_ipv4_set = False
     af_ipv6_set = False
-    proto_option_set: str | None = None
+    proto_option_set: Optional[str] = None
 
     args = None
     try: