unity – Why am i getting a “NullReferenceException: Object reference not set to an occasion of an object” Error when calling Listing.Comprises()?

So im attempting to make a randomized era engine for a high down dungeon crawler, within the Binding of Isaac Model, nonetheless, the code is throwing out a large number of errors when i strive it evaluate a price to a price within the record. the errors are on line 44,155,271,384, that are all if statements which are all formatted as such :if(gameMaster.PositionsOfRooms.Comprises(generatorPoint.rework.place))

Code Snippet:

public class DoorGenerator : MonoBehaviour

public bool isdoor;
public bool facingUp;
public bool facingDown;
public bool facingRight;
public bool facingLeft;
public bool generated;
public bool startingRoom = false;
public int runningRoomCount;
public GameObject generatorPoint;
public GameMasterScript gameMaster;
public Remodel teleportfromCords;
public Remodel teleporttoCords;
public GameObject digital camera;
// Begin known as earlier than the primary body replace
void Begin()
{
    gameMaster = GameObject.Discover("GameMaster").GetComponent<GameMasterScript>();
    teleportfromCords = rework.Discover("TeleportPoint");
    digital camera = GameObject.Discover("Predominant Digicam");
}

// Replace known as as soon as per body
void Replace()
{
    if(generated == false && gameMaster.targetRooms > gameMaster.roomsGenerated) 
    {
        GenerateRoom();


    }
}

public void GenerateRoom()
{if(generated ==false){
generated = true;
{
    if(facingUp == true)
        {
        generatorPoint = rework.father or mother.Discover("CreateRoomUp").gameObject;
        if(gameMaster.PositionsOfRooms.Comprises(new Vector3(generatorPoint.rework.place.x, generatorPoint.rework.place.y, generatorPoint.rework.place.z)))
        {
            return;
        }
        else
        {