docs: def _AddAttributeToCache(self, attribute_name, value, cache):
      """Helper to add a new attribute to a cache."""
      # If there's another value in cache with the same timestamp, the last added
      # one takes precedence. This helps a lot in tests that use FakeTime.
      attribute_list = cache.setdefault(attribute_name, [])
      if attribute_list and attribute_list[-1].age == value.age:
        attribute_list.pop()
  
      attribute_list.append(value)