fix linter warnings

bumble/device.py

@@ -3091,7 +3091,7 @@ class Device(CompositeEventEmitter):
     def on_pairing(
         self,
         connection: Connection,
-        identity_address: Address,
+        identity_address: Optional[Address],
         keys: PairingKeys,
         sc: bool,
     ) -> None:

bumble/keys.py

@@ -256,10 +256,11 @@ class JsonKeyStore(KeyStore):
     @staticmethod
     def from_device(device: Device, filename=None) -> Optional[JsonKeyStore]:
         if not filename:
-            # Extract the filename from the config
-            params = device.config.keystore.split(':', 1)[1:]
-            if params:
-                filename = params[0]
+            # Extract the filename from the config if there is one
+            if device.config.keystore is not None:
+                params = device.config.keystore.split(':', 1)[1:]
+                if params:
+                    filename = params[0]
 
         # Use a namespace based on the device address
         if device.public_address not in (Address.ANY, Address.ANY_RANDOM):

bumble/smp.py

@@ -1805,9 +1805,7 @@ class Manager(EventEmitter):
             self.device.abort_on('flush', store_keys())
 
         # Notify the device
-        self.device.on_pairing(
-            session.connection, identity_address, keys, session.sc
-        )
+        self.device.on_pairing(session.connection, identity_address, keys, session.sc)
 
     def on_pairing_failure(self, session: Session, reason: int) -> None:
         self.device.on_pairing_failure(session.connection, reason)