code: def config_value_changed(option):
      
      hook_data = unitdata.HookData()
      with hook_data():
          db = unitdata.kv()
          current = config(option)
          saved = db.get(option)
          db.set(option, current)
          if saved is None:
              return False
          return current != saved
docs: Determine if config value changed since last call to this function.