private TaskState Pickup(Dwarf d, float dt)
 {
     WorldObject m = d.GetActionbuilding().WithdrawWorldObject(d.GetActionMapElementType(), d.GetActionLevel());
     if (m == null)
         return TaskState.Fail;
     d.CarryWorldObject(m);
     d.SetActionBuilding(d.GetPrevActionBuilding());
     return TaskState.Success;
 }