mypy.

pymodbus/transport/stub.py

@@ -1,6 +1,8 @@
 """ModbusProtocol network stub."""
 from __future__ import annotations
 
+from typing import Callable
+
 from pymodbus.transport.transport import CommParams, ModbusProtocol
 
 
@@ -11,7 +13,7 @@ def __init__(
         self,
         params: CommParams,
         is_server: bool,
-        handler: callable | None = None,
+        handler: Callable[[bytes], bytes] | None = None,
     ) -> None:
         """Initialize a stub instance."""
         self.stub_handle_data = handler if handler else self.dummy_handler

test/test_network.py

@@ -1,4 +1,6 @@
 """Test transport."""
+from __future__ import annotations
+
 import asyncio
 
 import pytest
@@ -48,7 +50,7 @@ def local_handle_data(data: bytes) -> bytes | None:
             # 6 return 6 + 6 (wrong order
             # 8 return 7 + half 8
             # 9 return second half 8 + 9
-            if addr in (2, 5):
+            if addr in {2, 5}:
                 old_data = response
                 response = None
             elif addr == 3: