code: def swa_start(self) -> int:
      assert isinstance(self._swa_epoch_start, int)
      return max(self._swa_epoch_start - 1, 0)
  
imports: from copy import deepcopy
  from typing import Any, Callable, Dict, List, Optional, Union, cast
  import torch
  from torch import Tensor, nn
  from torch.optim.swa_utils import SWALR
  from typing_extensions import override
  import lightning.pytorch
  from lightning.fabric.utilities.types import LRScheduler
  from lightning.pytorch.callbacks.callback import Callback
  from lightning.pytorch.strategies import DeepSpeedStrategy
  from lightning.pytorch.strategies.fsdp import FSDPStrategy
  from lightning.pytorch.utilities.exceptions import MisconfigurationException
  from lightning.pytorch.utilities.rank_zero import rank_zero_info, rank_zero_warn
  from lightning.pytorch.utilities.types import LRSchedulerConfig
label_desc: Use image node_id 2 for calling the StochasticWeightAveraging obj's underlying member method code with example usage: obj.swa_start() and returns: max