diff --git a/django/core/cache/backends/base.py b/django/core/cache/backends/base.py
index 8adcdb9d49..a11ac71c95 100644
--- a/django/core/cache/backends/base.py
+++ b/django/core/cache/backends/base.py
@@ -394,6 +394,7 @@ class BaseCache:
             "configured correctly."
         )
 
+
 memcached_error_chars_re = _lazy_re_compile(r"[\x00-\x20\x7f]")
 
 
diff --git a/django/core/cache/backends/filebased.py b/django/core/cache/backends/filebased.py
index 8b9e18daab..41ee2689c0 100644
--- a/django/core/cache/backends/filebased.py
+++ b/django/core/cache/backends/filebased.py
@@ -14,6 +14,7 @@ from django.core.checks import Warning
 from django.core.files import locks
 from django.core.files.move import file_move_safe
 
+
 class FileBasedCache(BaseCache):
     cache_suffix = ".djcache"
     pickle_protocol = pickle.HIGHEST_PROTOCOL
diff --git a/django/core/checks/caches.py b/django/core/checks/caches.py
index 4986a800d2..857f8bf401 100644
--- a/django/core/checks/caches.py
+++ b/django/core/checks/caches.py
@@ -1,5 +1,4 @@
 import pathlib
-import json
 
 from django.conf import settings
 from django.core.cache import DEFAULT_CACHE_ALIAS, caches