plugins: psbt_nostr: add comment about testnet/mainnet separation

electrum/plugins/psbt_nostr/psbt_nostr.py

@@ -103,7 +103,9 @@ class CosignerWallet(Logger):
         self.cosigner_list = []  # type: List[Tuple[str, str]]
         self.nostr_pubkey = None
 
-        for key, keystore in wallet.keystores.items():
+        for keystore in wallet.get_keystores():
+            # note: there should be domain separation between testnet/mainnet.
+            #       Currently there is, due to the xpub str encoding it in its header.
             xpub = keystore.get_master_public_key()  # type: str
             privkey = sha256('nostr_psbt:' + xpub)
             pubkey = ecc.ECPrivkey(privkey).get_public_key_bytes()[1:]

electrum/wallet.py

@@ -4048,7 +4048,7 @@ class Multisig_Wallet(Deterministic_Wallet):
         return [k.derive_pubkey(c, i).hex() for k in self.get_keystores()]
 
     def load_keystore(self):
-        self.keystores = {}
+        self.keystores = {}  # type: Dict[str, KeyStore]
         for i in range(self.n):
             name = 'x%d' % (i+1)
             self.keystores[name] = load_keystore(self.db, name)