Keys on Doors...

[JMFStorm]

2)main (8,24) : ERR : 'mansion_2' is not declared
3)main (9,5) : ERR : No matching signatures to 'PlaySoundAtEntity(string@&, string@&, int, const uint, const bool)
6)main (10,16) : ERR : 'studykey_1' is not declared

You don't know how to read? The errors are indicated right here. Just copy paste this over your current so it all probably starts to work:

void OnStart()
{
AddUseItemCallback("", "studykey_1", "mansion_2", "OPEN", true);
}

void OPEN(string &in asItem, string &in asEntity)
{
SetSwingDoorLocked("mansion_2", false, true);
PlaySoundAtEntity("", "unlock_door", "mansion_2", 0, false);
RemoveItem("studykey_1");
}