code: def prefetch_state(self, p):
      if self.is_paged:
          state = self.state[p]
          s1 = state["state1"]
          is_paged = getattr(s1, "is_paged", False)
          if is_paged:
              F.prefetch_tensor(state["state1"])
              if "state2" in state:
                  F.prefetch_tensor(state["state2"])
  
imports: from collections import abc
  from collections import defaultdict
  from copy import deepcopy
  from itertools import chain
  import torch
  import bitsandbytes.functional
label_desc: Use image node_id 12 for calling the Optimizer8bit obj's underlying member method code with example usage: obj.prefetch_state(p) without return types