diff --git a/telebot/__init__.py b/telebot/__init__.py
index 53ea22d..e379435 100644
--- a/telebot/__init__.py
+++ b/telebot/__init__.py
@@ -3140,10 +3140,10 @@ class TeleBot:
         filter_check = self.custom_filters.get(message_filter)
         if not filter_check:
             return False
-        elif isinstance(filter_value, util.SimpleCustomFilter):
+        elif isinstance(filter_check, util.SimpleCustomFilter):
             return filter_value == filter_check.check(message)
-        elif isinstance(filter_value, util.AdvancedCustomFilter):
-            return filter_check.check(message,filter_value)
+        elif isinstance(filter_check, util.AdvancedCustomFilter):
+            return filter_check.check(message, filter_value)
         else:
             logger.error("Custom filter: wrong type. Should be SimpleCustomFilter or AdvancedCustomFilter.")
             return False
diff --git a/telebot/util.py b/telebot/util.py
index 88019ad..8607ff2 100644
--- a/telebot/util.py
+++ b/telebot/util.py
@@ -5,6 +5,7 @@ import string
 import threading
 import traceback
 from typing import Any, Callable, List, Dict, Optional, Union
+from abc import ABC
 
 # noinspection PyPep8Naming
 import queue as Queue
@@ -457,20 +458,20 @@ def webhook_google_functions(bot, request):
         return 'Bot ON'
 
 
-class SimpleCustomFilter:
+class SimpleCustomFilter(ABC):
     """
     Simple Custom Filter base class.
     Create child class with check() method.
     Accepts only bool.
     """
 
-    def check(message):
+    def check(self, message):
         """
         Perform a check.
         """
         pass
 
-class AdvancedCustomFilter:
+class AdvancedCustomFilter(ABC):
     """
     Simple Custom Filter base class.
     Create child class with check() method.
@@ -479,8 +480,8 @@ class AdvancedCustomFilter:
     text: Filter value given in handler
     """
 
-    def check(message, text):
+    def check(self, message, text):
         """
         Perform a check.
         """
-        pass
\ No newline at end of file
+        pass