Do tox lint and reformat

aleksis/core/templatetags/html_helpers.py

 import random
 import string
-
 from urllib.parse import urlparse
 
 from django import template
@@ -32,7 +31,7 @@ def add_class_to_el(value: str, arg: str) -> str:
 
 @register.filter
 def remove_prefix(value: str, prefix: str) -> str:
-    """Remove prefix of a url
+    """Remove prefix of a url.
 
     :Example:
 
@@ -43,7 +42,7 @@ def remove_prefix(value: str, prefix: str) -> str:
     url = urlparse(value)
 
     if url.path.startswith(prefix):
-        url = url._replace(path=url.path[len(prefix):])
+        url = url._replace(path=url.path[len(prefix) :])
 
     return url.geturl()