diff --git a/electrum/invoices.py b/electrum/invoices.py
index 2791258bc..59065162e 100644
--- a/electrum/invoices.py
+++ b/electrum/invoices.py
@@ -107,8 +107,16 @@ class BaseInvoice(StoredObject):
     #bip70_requestor = attr.ib(type=str, kw_only=True)  # type: Optional[str]
 
 
-    def is_lightning(self):
-        return self.lightning_invoice is not None
+    def is_lightning(self) -> bool:
+        raise NotImplementedError()
+
+    def get_address(self) -> Optional[str]:
+        """returns the first address, to be displayed in GUI"""
+        raise NotImplementedError()
+
+    @property
+    def rhash(self) -> str:
+        raise NotImplementedError()
 
     def get_status_str(self, status):
         status_str = pr_tooltips[status]
@@ -240,8 +248,10 @@ class Invoice(BaseInvoice):
     lightning_invoice = attr.ib(type=str, kw_only=True)  # type: Optional[str]
     __lnaddr = None
 
+    def is_lightning(self):
+        return self.lightning_invoice is not None
+
     def get_address(self) -> Optional[str]:
-        """returns the first address, to be displayed in GUI"""
         address = None
         if self.outputs:
             address = self.outputs[0].address if len(self.outputs) > 0 else None
@@ -257,6 +267,7 @@ class Invoice(BaseInvoice):
 
     @property
     def rhash(self) -> str:
+        assert self.is_lightning()
         return self._lnaddr.paymenthash.hex()
 
     @lightning_invoice.validator
@@ -295,7 +306,6 @@ class Request(BaseInvoice):
         return self.payment_hash is not None
 
     def get_address(self) -> Optional[str]:
-        """returns the first address, to be displayed in GUI"""
         address = None
         if self.outputs:
             address = self.outputs[0].address if len(self.outputs) > 0 else None
@@ -303,9 +313,10 @@ class Request(BaseInvoice):
 
     @property
     def rhash(self) -> str:
+        assert self.is_lightning()
         return self.payment_hash.hex()
 
 
-def get_id_from_onchain_outputs(outputs: List[PartialTxOutput], *, timestamp: int) -> str:
+def get_id_from_onchain_outputs(outputs: Sequence[PartialTxOutput], *, timestamp: int) -> str:
     outputs_str = "\n".join(f"{txout.scriptpubkey.hex()}, {txout.value}" for txout in outputs)
     return sha256d(outputs_str + "%d" % timestamp).hex()[0:10]
diff --git a/electrum/lnworker.py b/electrum/lnworker.py
index 5ecaaabb7..eae2ac43a 100644
--- a/electrum/lnworker.py
+++ b/electrum/lnworker.py
@@ -30,6 +30,7 @@ from . import constants, util
 from . import keystore
 from .util import profiler, chunks, OldTaskGroup
 from .invoices import Invoice, PR_UNPAID, PR_EXPIRED, PR_PAID, PR_INFLIGHT, PR_FAILED, PR_ROUTING, LN_EXPIRY_NEVER
+from .invoices import BaseInvoice
 from .util import NetworkRetryManager, JsonRPCClient, NotEnoughFunds
 from .util import EventListener, event_listener
 from .lnutil import LN_MAX_FUNDING_SAT
@@ -1899,7 +1900,7 @@ class LNWallet(LNWorker):
         info = self.get_payment_info(payment_hash)
         return info.status if info else PR_UNPAID
 
-    def get_invoice_status(self, invoice: Invoice) -> int:
+    def get_invoice_status(self, invoice: BaseInvoice) -> int:
         invoice_id = invoice.rhash
         if invoice_id in self.inflight_payments:
             return PR_INFLIGHT
@@ -2291,7 +2292,7 @@ class LNWallet(LNWorker):
         return await self.pay_invoice(
             invoice, channels=[chan1])
 
-    def can_receive_invoice(self, invoice: Invoice) -> bool:
+    def can_receive_invoice(self, invoice: BaseInvoice) -> bool:
         assert invoice.is_lightning()
         return (invoice.get_amount_sat() or 0) <= self.num_sats_can_receive()
 
diff --git a/electrum/wallet.py b/electrum/wallet.py
index bc6661ebf..a1d607518 100644
--- a/electrum/wallet.py
+++ b/electrum/wallet.py
@@ -2361,11 +2361,11 @@ class Abstract_Wallet(ABC, Logger, EventListener):
     def delete_address(self, address: str) -> None:
         raise Exception("this wallet cannot delete addresses")
 
-    def get_request_URI(self, req: Invoice) -> Optional[str]:
+    def get_request_URI(self, req: Request) -> Optional[str]:
         include_lightning = bool(self.config.get('bip21_lightning', False))
         return req.get_bip21_URI(include_lightning=include_lightning)
 
-    def check_expired_status(self, r: Invoice, status):
+    def check_expired_status(self, r: BaseInvoice, status):
         #if r.is_lightning() and r.exp == 0:
         #    status = PR_EXPIRED  # for BOLT-11 invoices, exp==0 means 0 seconds
         if status == PR_UNPAID and r.has_expired():
@@ -2850,7 +2850,7 @@ class Abstract_Wallet(ABC, Logger, EventListener):
         else:
             return allow_send, long_warning, short_warning
 
-    def get_help_texts_for_receive_request(self, req: Invoice) -> ReceiveRequestHelp:
+    def get_help_texts_for_receive_request(self, req: Request) -> ReceiveRequestHelp:
         key = req.get_id()
         addr = req.get_address() or ''
         amount_sat = req.get_amount_sat() or 0