Kache ,Gson , Cant Convert it Back To Kache Object , build Error

[blackholeearth]

after i restart the i app i want to access same memory cache.

is it possible??

[blackholeearth]

i am trying convert Kache to json , and reverse .
but i get buildError: Only classes are allowed on the left hand side of a class literal

code:

 
    fun save_Kache(kacheobj: InMemoryKache<List<Int>,List<Media>>) {
        sharedPref.edit().putString("kacheobj", Gson().toJson(kacheobj)).apply()
    }

    fun get_Kache(): InMemoryKache<List<Int>, List<Media>>? {
        val data = sharedPref.getString("kacheobj", null)
        if (data == null) {
            return null
        }
        return Gson().fromJson(data, InMemoryKache<List<Int>,List<Media>>::class.java) //buildError:
    }