diff --git a/mypy.ini b/mypy.ini
index f00b3eeb6bac..927ad0f89586 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -2,4 +2,4 @@
 ignore_missing_imports = True
 install_types = True
 non_interactive = True
-exclude = (other/least_recently_used.py|other/lfu_cache.py|other/lru_cache.py)
+exclude = (other/lfu_cache.py|other/lru_cache.py)
diff --git a/other/least_recently_used.py b/other/least_recently_used.py
index d0e27efc6dc8..302a06c1fd3b 100644
--- a/other/least_recently_used.py
+++ b/other/least_recently_used.py
@@ -1,16 +1,17 @@
 import sys
-from abc import abstractmethod
+from abc import ABCMeta
 from collections import deque
 
 
 class LRUCache:
     """Page Replacement Algorithm, Least Recently Used (LRU) Caching."""
 
+    __metaclass__ = ABCMeta
+
     dq_store = object()  # Cache store of keys
     key_reference_map = object()  # References of the keys in cache
     _MAX_CAPACITY: int = 10  # Maximum capacity of cache
 
-    @abstractmethod
     def __init__(self, n: int):
         """Creates an empty store and map for the keys.
         The LRUCache is set the size n.