diff --git a/electrum/channel_db.py b/electrum/channel_db.py
index f6bc54417..3b8cd578c 100644
--- a/electrum/channel_db.py
+++ b/electrum/channel_db.py
@@ -254,7 +254,7 @@ class ChannelDB(SqlDB):
         # initialized in load_data
         self._channels = {}  # type: Dict[bytes, ChannelInfo]
         self._policies = {}  # type: Dict[Tuple[bytes, bytes], Policy]  # (node_id, scid) -> Policy
-        self._nodes = {}
+        self._nodes = {}  # type: Dict[bytes, NodeInfo]  # node_id -> NodeInfo
         # node_id -> (host, port, ts)
         self._addresses = defaultdict(set)  # type: Dict[bytes, Set[Tuple[str, int, int]]]
         self._channels_for_node = defaultdict(set)  # type: Dict[bytes, Set[ShortChannelID]]
diff --git a/electrum/lnonion.py b/electrum/lnonion.py
index 7d61f9d02..a198fe364 100644
--- a/electrum/lnonion.py
+++ b/electrum/lnonion.py
@@ -26,8 +26,8 @@
 import hashlib
 from typing import Sequence, List, Tuple, NamedTuple, TYPE_CHECKING
 from enum import IntEnum, IntFlag
-from Cryptodome.Cipher import ChaCha20
 
+from Cryptodome.Cipher import ChaCha20
 
 from . import ecc
 from .crypto import sha256, hmac_oneshot
@@ -231,9 +231,10 @@ def generate_cipher_stream(stream_key: bytes, num_bytes: int) -> bytes:
     return cipher.encrypt(bytes(num_bytes))
 
 
-ProcessedOnionPacket = NamedTuple("ProcessedOnionPacket", [("are_we_final", bool),
-                                                           ("hop_data", OnionHopsDataSingle),
-                                                           ("next_packet", OnionPacket)])
+class ProcessedOnionPacket(NamedTuple):
+    are_we_final: bool
+    hop_data: OnionHopsDataSingle
+    next_packet: OnionPacket
 
 
 # TODO replay protection
diff --git a/electrum/lnpeer.py b/electrum/lnpeer.py
index 2bfcfa64d..83cf8ffef 100644
--- a/electrum/lnpeer.py
+++ b/electrum/lnpeer.py
@@ -320,7 +320,7 @@ class Peer(Logger):
         try:
             await asyncio.wait_for(self.initialized, LN_P2P_NETWORK_TIMEOUT)
         except Exception as e:
-            raise GracefulDisconnect(f"Failed to initialize: {e}") from e
+            raise GracefulDisconnect(f"Failed to initialize: {e!r}") from e
         if self.lnworker == self.lnworker.network.lngossip:
             try:
                 ids, complete = await asyncio.wait_for(self.get_channel_range(), LN_P2P_NETWORK_TIMEOUT)
diff --git a/electrum/lnworker.py b/electrum/lnworker.py
index c2d86348b..31a0a7fd4 100644
--- a/electrum/lnworker.py
+++ b/electrum/lnworker.py
@@ -7,7 +7,7 @@ import os
 from decimal import Decimal
 import random
 import time
-from typing import Optional, Sequence, Tuple, List, Dict, TYPE_CHECKING
+from typing import Optional, Sequence, Tuple, List, Dict, TYPE_CHECKING, NamedTuple
 import threading
 import socket
 import json
@@ -106,8 +106,6 @@ FALLBACK_NODE_LIST_MAINNET = [
 ]
 
 
-from typing import NamedTuple
-
 class PaymentInfo(NamedTuple):
     payment_hash: bytes
     amount: int
diff --git a/electrum/transaction.py b/electrum/transaction.py
index e777611a4..041d5b1d6 100644
--- a/electrum/transaction.py
+++ b/electrum/transaction.py
@@ -180,7 +180,7 @@ class TxOutpoint(NamedTuple):
     def to_str(self) -> str:
         return f"{self.txid.hex()}:{self.out_idx}"
 
-    def to_json(self) -> str:
+    def to_json(self):
         return [self.txid.hex(), self.out_idx]
 
     def serialize_to_network(self) -> bytes: