def index_to_filename(
        self, dataset: Optional[Union[LightlyDataset, None]], index_subset: int
    ) -> str:
        """Converts a subset index to its corresponding filename.

        Args:
            dataset:
                Unused parameter to match the parent class method signature.
            index_subset:
                The index of the sample within the subset.

        Returns:
            The filename of the sample at the specified subset index.
        """
        fname = self.filenames_subset[index_subset]
        return fname
Converts a subset index to its corresponding filename.

        Args:
            dataset:
                Unused parameter to match the parent class method signature.
            index_subset:
                The index of the sample within the subset.

        Returns:
            The filename of the sample at the specified subset index.
        
lightly/data/lightly_subset.py