def _reload_docs(
        cls, collection_name, sample_ids=None, hard=False, include_frames=False
    ):
        """Reloads the backing documents for in-memory samples in the
        collection.

        If ``sample_ids`` are provided, only those samples are reloaded.
        """
        if collection_name not in cls._instances:
            return

        samples = cls._instances[collection_name]

        if sample_ids is not None:
            sample_ids = set(str(_id) for _id in sample_ids)
            for sample in samples.values():
                if sample.id in sample_ids:
                    sample.reload(hard=hard, include_frames=include_frames)
        else:
            for sample in samples.values():
                sample.reload(hard=hard, include_frames=include_frames)
Reloads the backing documents for in-memory samples in the
        collection.

        If ``sample_ids`` are provided, only those samples are reloaded.
        
fiftyone/core/singletons.py