remove dead code

src/rule.py

@@ -285,11 +285,6 @@ class Ruleset:
     hits = 0
     misses = 0
 
-    @staticmethod
-    def clearCache():
-        """clears the cache with Rulesets"""
-        Ruleset.cache.clear()
-
     @staticmethod
     def cached(name):
         """If a Ruleset instance is never changed, we can use a cache"""