use old python syntax

Author: Karim Shamazov

tests/python/lib/tcp.py

@@ -1,4 +1,5 @@
 import socketserver
+from typing import Optional
 
 
 class HelloHandler(socketserver.BaseRequestHandler):
@@ -10,7 +11,7 @@ class Server(socketserver.TCPServer):
     allow_reuse_address = True
 
 
-def make_server(port: int | None) -> Server | None:
+def make_server(port: Optional[int]) -> Optional[Server]:
     if port:
         return Server(('localhost', port), HelloHandler)
     return None