code: def reset(self) -> None:
      self.fetched = 0
      # teardown calls `reset()`, and if it happens early, `combined_loader` can still be None
      if self._combined_loader is not None:
          self.length = sized_len(self.combined_loader)
          self.done = self.length == 0
  
imports: from typing import Any, Iterator, List, Optional
  from typing_extensions import override
  from lightning.fabric.utilities.data import sized_len
  from lightning.pytorch.utilities.combined_loader import _ITERATOR_RETURN, CombinedLoader
  from lightning.pytorch.utilities.exceptions import MisconfigurationException
label_desc: Use image node_id 6 for calling the _DataFetcher obj's underlying member method code with example usage: obj.reset() without return types