wallet: remove method get_num_tx

electrum/address_synchronizer.py

@@ -102,6 +102,7 @@ class AddressSynchronizer(PrintError):
         return h
 
     def get_address_history_len(self, addr: str) -> int:
+        """Return number of transactions where address is involved."""
         return len(self._history_local.get(addr, ()))
 
     def get_txin_address(self, txi):
@@ -617,10 +618,6 @@ class AddressSynchronizer(PrintError):
     def is_up_to_date(self):
         with self.lock: return self.up_to_date
 
-    def get_num_tx(self, address):
-        """ return number of transactions where address is involved """
-        return len(self.history.get(address, []))
-
     def get_tx_delta(self, tx_hash, address):
         "effect of tx on address"
         delta = 0

electrum/wallet.py

@@ -563,7 +563,7 @@ class Abstract_Wallet(AddressSynchronizer):
                 # confirmations.  Select the unused addresses within the
                 # gap limit; if none take one at random
                 change_addrs = [addr for addr in addrs if
-                                self.get_num_tx(addr) == 0]
+                                self.get_address_history_len(addr) == 0]
                 if not change_addrs:
                     change_addrs = [random.choice(addrs)]
             else: