diff --git a/rhodecode/lib/diffs.py b/rhodecode/lib/diffs.py
index 6a756811..4b3b9241 100644
--- a/rhodecode/lib/diffs.py
+++ b/rhodecode/lib/diffs.py
@@ -269,13 +269,15 @@ class DiffProcessor(object):
         end += 1
         if start or end:
 
-            def do(l):
-                last = end + len(l["line"])
-                if l["action"] == Action.ADD:
+            def do(_line):
+                last = end + len(_line["line"])
+                if _line["action"] == Action.ADD:
                     tag = "ins"
                 else:
                     tag = "del"
-                l["line"] = f"{l['line'][:start]}<{tag}>{l['line'][start:last]}</{tag}>{l['line'][last:]}"
+                _line["line"] = (
+                    f"{_line['line'][:start]}<{tag}>{_line['line'][start:last]}</{tag}>{_line['line'][last:]}"
+                )
 
             do(line)
             do(next_)
@@ -1045,8 +1047,8 @@ class DiffLimitExceeded(Exception):
 
 
 # NOTE(marcink): if diffs.mako change, probably this
-# needs a bump to next version
-CURRENT_DIFF_VERSION = "v5"
+# needs a bump to the next version
+CURRENT_DIFF_VERSION = "v6"
 
 
 def _cleanup_cache_file(cached_diff_file):