diff --git a/torba/torba/client/baseledger.py b/torba/torba/client/baseledger.py
index 6fb8cea99..1db56885f 100644
--- a/torba/torba/client/baseledger.py
+++ b/torba/torba/client/baseledger.py
@@ -191,12 +191,14 @@ class BaseLedger(metaclass=LedgerRegistry):
         if match:
             account, address_info = match
             return account.get_private_key(address_info['chain'], address_info['position'])
+        return None
 
     async def get_public_key_for_address(self, address) -> Optional[PubKey]:
         match = await self._get_account_and_address_info_for_address(address)
         if match:
             account, address_info = match
             return account.get_public_key(address_info['chain'], address_info['position'])
+        return None
 
     async def get_account_for_address(self, address):
         match = await self._get_account_and_address_info_for_address(address)
diff --git a/torba/torba/client/basetransaction.py b/torba/torba/client/basetransaction.py
index 6986ea39c..0edf6c8b8 100644
--- a/torba/torba/client/basetransaction.py
+++ b/torba/torba/client/basetransaction.py
@@ -532,6 +532,7 @@ class BaseTransaction:
             if txo_script.is_pay_pubkey_hash:
                 address = ledger.hash160_to_address(txo_script.values['pubkey_hash'])
                 private_key = await ledger.get_private_key_for_address(address)
+                assert private_key is not None
                 tx = self._serialize_for_signature(i)
                 txi.script.values['signature'] = \
                     private_key.sign(tx) + bytes((self.signature_hash_type(1),))