diff --git a/telethon/utils.py b/telethon/utils.py
index ab78d8a4..1c939e98 100644
--- a/telethon/utils.py
+++ b/telethon/utils.py
@@ -756,7 +756,10 @@ def sanitize_parse_mode(mode):
     if not mode:
         return None
 
-    if callable(mode):
+    if (all(hasattr(mode, x) for x in ('parse', 'unparse'))
+          and all(callable(x) for x in (mode.parse, mode.unparse))):
+        return mode
+    elif callable(mode):
         class CustomMode:
             @staticmethod
             def unparse(text, entities):
@@ -764,9 +767,6 @@ def sanitize_parse_mode(mode):
 
         CustomMode.parse = mode
         return CustomMode
-    elif (all(hasattr(mode, x) for x in ('parse', 'unparse'))
-          and all(callable(x) for x in (mode.parse, mode.unparse))):
-        return mode
     elif isinstance(mode, str):
         try:
             return {