diff --git a/aioax25/peer.py b/aioax25/peer.py
index 892be6b..b155982 100644
--- a/aioax25/peer.py
+++ b/aioax25/peer.py
@@ -1580,7 +1580,7 @@ def _update_state(self, prop, delta=None, value=None, comment=""):
             comment += " delta=%s" % delta
 
         # Always apply modulo op (assume 8 if not set)
-        value %= (self._modulo or 8)
+        value %= self._modulo or 8
 
         self._log.debug(
             "%s = %s" + comment, getattr(self, "%s_name" % prop), value
diff --git a/aioax25/tools/listen.py b/aioax25/tools/listen.py
index ed66242..a68e9b7 100644
--- a/aioax25/tools/listen.py
+++ b/aioax25/tools/listen.py
@@ -92,9 +92,11 @@ def __init__(self, peer, command, echo, log):
     async def init(self):
         self._log.info("Launching sub-process")
         await asyncio.get_event_loop().subprocess_exec(
-            self._make_protocol, *self._command,
+            self._make_protocol,
+            *self._command,
             stdout=subprocess.PIPE,
-            stderr=subprocess.STDOUT, bufsize=0
+            stderr=subprocess.STDOUT,
+            bufsize=0
         )
 
     def _make_protocol(self):
@@ -209,7 +211,12 @@ def _on_connection_request(self, peer, **kwargs):
     async def _connect_peer(self, peer):
         self._log.info("Incoming connection from %s", peer.address)
         try:
-            session = PeerSession(peer, self._command, self._echo, self._log.getChild(str(peer.address)))
+            session = PeerSession(
+                peer,
+                self._command,
+                self._echo,
+                self._log.getChild(str(peer.address)),
+            )
             await session.init()
         except:
             self._log.exception("Failed to initialise peer connection")
@@ -225,14 +232,20 @@ async def main():
 
     ap.add_argument("--log-level", default="info", type=str, help="Log level")
     ap.add_argument("--port", default=0, type=int, help="KISS port number")
-    ap.add_argument("--echo", default=False, action="store_const", const=True,
-                    help="Echo input back to the caller")
+    ap.add_argument(
+        "--echo",
+        default=False,
+        action="store_const",
+        const=True,
+        help="Echo input back to the caller",
+    )
     ap.add_argument(
         "config", type=str, help="KISS serial port configuration file"
     )
     ap.add_argument("source", type=str, help="Source callsign/SSID")
-    ap.add_argument("command", type=str, nargs="+",
-                    help="Program + args to run")
+    ap.add_argument(
+        "command", type=str, nargs="+", help="Program + args to run"
+    )
 
     args = ap.parse_args()
 
@@ -245,8 +258,9 @@ async def main():
     )
     config = safe_load(open(args.config, "r").read())
 
-    ax25listen = AX25Listen(args.source, args.command, config, args.port,
-                            args.echo)
+    ax25listen = AX25Listen(
+        args.source, args.command, config, args.port, args.echo
+    )
     await ax25listen.listen()