txbatcher: add comment to _to_pay_after

electrum/network.py

@@ -1069,7 +1069,7 @@ class Network(Logger, NetworkRetryManager[ServerAddr]):
             raise RequestTimedOut()
         await self.interface.broadcast_transaction(tx, timeout=timeout)
 
-    async def try_broadcasting(self, tx, name) -> bool:
+    async def try_broadcasting(self, tx: 'Transaction', name: str) -> bool:
         try:
             await self.broadcast_transaction(tx)
         except Exception as e:

electrum/transaction.py

@@ -203,6 +203,9 @@ class TxOutput:
     def __ne__(self, other):
         return not (self == other)
 
+    def __hash__(self) -> int:
+        return hash((self.scriptpubkey, self.value))
+
     def to_json(self):
         d = {
             'scriptpubkey': self.scriptpubkey.hex(),

electrum/txbatcher.py

@@ -303,6 +303,8 @@ class TxBatch(Logger):
     def _to_pay_after(self, tx: Optional[PartialTransaction]) -> Sequence[PartialTxOutput]:
         if not tx:
             return self.batch_payments
+        # note: the below is equivalent to
+        #   to_pay = multiset(self.batch_payments) - multiset(tx.outputs())
         to_pay = []
         outputs = copy.deepcopy(tx.outputs())
         for x in self.batch_payments: