Verify blacklist correctly

freqtrade/pairlist/IPairList.py

@@ -57,14 +57,22 @@ class IPairList(ABC):
         """
 
     @staticmethod
-    def _verify_blacklist(self, pairlist: List[str]) -> List[str]:
-
+    def verify_blacklist(self, pairlist: List[str], blacklist: List[str]) -> List[str]:
+        """
+        Verify and remove items from pairlist - returning a filtered pairlist.
+        """
         for pair in deepcopy(pairlist):
-            if pair in self._pairlistmanager.blacklist:
+            if pair in blacklist:
                 logger.warning(f"Pair {pair} in your blacklist. Removing it from whitelist...")
                 pairlist.remove(pair)
         return pairlist
 
+    def _verify_blacklist(self, pairlist: List[str]) -> List[str]:
+        """
+        Proxy method to verify_blacklist for easy access for child classes.
+        """
+        return IPairList.verify_blacklist(pairlist, self._pairlistmanager.blacklist)
+
     def _whitelist_for_active_markets(self, whitelist: List[str]) -> List[str]:
         """
         Check available markets and remove pair from whitelist if necessary

freqtrade/pairlist/pairlistmanager.py

@@ -61,5 +61,6 @@ class PairListManager():
             pairlist = pl.filter_pairlist(pairlist, tickers)
 
         # Validation against blacklist happens after the pairlists to ensure blacklist is respected.
-        pairlist = self.verify_blacklist(pairlist, self.blacklist)
+        pairlist = IPairList.verify_blacklist(pairlist, self.blacklist)
+
         self._whitelist = pairlist