fix: further improve exchange.close fix

freqtrade/exchange/exchange.py

@@ -314,9 +314,10 @@ class Exchange:
         if self._exchange_ws:
             self._exchange_ws.cleanup()
         logger.debug("Exchange object destroyed, closing async loop")
-        loop_running = (
-            getattr(self, "loop", None) and self.loop.is_running()
-        ) or asyncio.get_event_loop().is_running()
+        generic_loop = asyncio.get_event_loop()
+        loop_running = (getattr(self, "loop", None) and self.loop.is_running()) or (
+            generic_loop and generic_loop.is_running()
+        )
 
         if (
             getattr(self, "_api_async", None)