From bf89cf2b4bf338adef31d21eb33b41b050794309 Mon Sep 17 00:00:00 2001
From: Mateusz Mandera <mateusz.mandera@protonmail.com>
Date: Mon, 30 Dec 2019 02:26:08 +0100
Subject: [PATCH] rate_limiter: Use ABC for defining the abstract class
 RateLimitedObject.

---
 zerver/lib/rate_limiter.py | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/zerver/lib/rate_limiter.py b/zerver/lib/rate_limiter.py
index 52c64e0609..4d406ad922 100644
--- a/zerver/lib/rate_limiter.py
+++ b/zerver/lib/rate_limiter.py
@@ -1,5 +1,6 @@
 import os
 
+from abc import ABC, abstractmethod
 from typing import Dict, List, Optional, Tuple
 
 from django.conf import settings
@@ -27,20 +28,23 @@ logger = logging.getLogger(__name__)
 class RateLimiterLockingException(Exception):
     pass
 
-class RateLimitedObject:
+class RateLimitedObject(ABC):
     def get_keys(self) -> List[str]:
         key_fragment = self.key_fragment()
         return ["{}ratelimit:{}:{}".format(KEY_PREFIX, key_fragment, keytype)
                 for keytype in ['list', 'zset', 'block']]
 
+    @abstractmethod
     def key_fragment(self) -> str:
-        raise NotImplementedError()
+        pass
 
+    @abstractmethod
     def rules(self) -> List[Tuple[int, int]]:
-        raise NotImplementedError()
+        pass
 
+    @abstractmethod
     def __str__(self) -> str:
-        raise NotImplementedError()
+        pass
 
 class RateLimitedUser(RateLimitedObject):
     def __init__(self, user: UserProfile, domain: str='api_by_user') -> None: