code: def parse(self, target):
          
          if isinstance(target, ContentNode):
              if target.name:
                  self.parent = target
                  self.name.parse(self)
                  self.name += target.name
              target.ruleset.append(self)
          self.root.cache['rset'][str(self.name).split()[0]].add(self)
          super(Ruleset, self).parse(target)
docs: Parse nested rulesets
              and save it in cache.