Fixed leftovers from refactoring

wumpus/wumpus.py

@@ -165,7 +165,7 @@ class Hunter(Agent):
 
     @property
     def glitter(self):
-        return self.world.isGold(self.location)
+        return self.world.isGold(self.location) is not None
 
     @property
     def bump(self):
@@ -212,7 +212,8 @@ class Hunter(Agent):
                 reward -= 1
         elif action == self.Actions.GRAB:
             reward -= 1
-            for gold in self.world.isGold(self.location):
+            gold = self.world.isGold(self.location)
+            if gold:
                 self._has_gold = True
                 self.world.removeObject(gold)
         elif action == self.Actions.CLIMB:
@@ -338,7 +339,7 @@ class WumpusWorld(GridWorld):
         """Return a gold if it's at the coordinate or None."""
         return next(iter(self._objAt(Gold, pos)), None)
 
-    def isExit(self, pos: Coordinate) -> Iterable[Exit]:
+    def isExit(self, pos: Coordinate) -> Exit:
         """Return a exit if it's at the coordinate or None."""
         return next(iter(self._objAt(Exit, pos)), None)