diff --git a/electrum/lnonion.py b/electrum/lnonion.py
index 07385151a543..f3db1c1aa9f1 100644
--- a/electrum/lnonion.py
+++ b/electrum/lnonion.py
@@ -175,7 +175,7 @@ def get_shared_secrets_along_route(payment_path_pubkeys: Sequence[bytes],
 
 
 def get_shared_secrets_along_route2(payment_path_pubkeys_plus: Sequence[Union[bytes, Tuple[bytes, bytes]]],
-                                    session_key: bytes) -> tuple[Sequence[bytes], Sequence[bytes]]:
+                                    session_key: bytes) -> Tuple[Sequence[bytes], Sequence[bytes]]:
     num_hops = len(payment_path_pubkeys_plus)
     hop_shared_secrets = num_hops * [b'']
     hop_blinded_node_ids = num_hops * [b'']
@@ -251,7 +251,7 @@ def new_onion_packet(
 
 
 def new_onion_packet2(
-    payment_path_pubkeys: Sequence[Union[bytes, tuple]],
+    payment_path_pubkeys: Sequence[Union[bytes, Tuple[bytes, bytes]]],
     session_key: bytes,
     hops_data: Sequence[OnionHopsDataSingle],
     *,
@@ -374,7 +374,7 @@ def process_onion_packet(
         onion_packet: OnionPacket,
         our_onion_private_key: bytes,
         *,
-        associated_data: bytes = bytes(),
+        associated_data: bytes = b'',
         is_trampoline=False,
         tlv_stream_name='payload') -> ProcessedOnionPacket:
     if not ecc.ECPubkey.is_pubkey_bytes(onion_packet.public_key):
diff --git a/electrum/onion_message.py b/electrum/onion_message.py
index 5982d094f892..68894a714439 100644
--- a/electrum/onion_message.py
+++ b/electrum/onion_message.py
@@ -37,6 +37,7 @@
 
 if TYPE_CHECKING:
     from electrum.lnworker import LNWallet
+    from electrum.network import Network
 
 logger = get_logger(__name__)
 
diff --git a/tests/test_bolt12.py b/tests/test_bolt12.py
index 7af2e66d6736..8b6e75fc5729 100644
--- a/tests/test_bolt12.py
+++ b/tests/test_bolt12.py
@@ -272,8 +272,15 @@ def test_serde_complex_fields(self):
             ]}
         }
 
-        with self.assertRaises(Exception):
+        # assertRaises on generic Exception used in lnmsg encode/write_tlv_stream makes flake8 complain
+        # so work around this for now (TODO: refactor lnmsg generic exceptions)
+        #with self.assertRaises(Exception):
+        try:
             invreq_pl_tlv = encode_invoice_request(invreq, payer_key=payer_key)
+        except Exception as e:
+            pass
+        else:
+            raise Exception('Exception expected')
 
         # test complex field count matches parameters
         invreq = {