```
    classification_result = await classify_all_items(
        unclassified,
        group_definitions,
        current_user=current_user,
        batch_size=batch_size,
    )
    classifications = classification_result["classified_groups"]
    # unique_items = [{v.id: v} for v in classifications.values()]
    classification_failures = classification_result["failed_items"]
    total_failed += len(classification_failures)
    logger.info("")

    for group_name, group_items in classifications.items():
        # The LLM functions have aggregated item IDs into groups.
        # But now we need to match the group names to output feeds and put the items
        # into the DB.
        # We're matching based on name because the LLM isn't given IDs.
        # We can be confident that the name is unique in the catalogue.
        logger.debug(
            f"Trying to find an output feed called '{group_name}' to match it to the "
            "LLM response",
            extra={"group_name": group_name},
        )
        output_feed = next(
            (feed for feed in output_feeds if feed.title == group_name), None
        )
        if not output_feed:
            logger.error(
                f"LLM gave name {group_name}, but it's not an output feed.",
                extra={"group_name": group_name},
            )
            # All items in this group are consequently failed
            total_failed += len(group_items)
            continue
        logger.debug(f"Found an output feed called '{group_name}', now matching items")
        for llm_item in group_items:
            db_item = next(
                (item for item in unclassified if item.id == llm_item.id),
                None,
            )

            if db_item:
                await session.refresh(db_item)
                existing_classifications_result = await session.exec(
                    select(ItemFeedLink).where(
                        ItemFeedLink.item_id == db_item.id,
                        ItemFeedLink.feed_id.in_([feed.id for feed in output_feeds]),
                    )
                )
                existing_classifications = existing_classifications_result.all()
                if existing_classifications:
                    logger.warning(
                        "Surprised to find at least one existing classification",
                        extra={
                            "item_id": db_item.id,
                            "feed_id": existing_classifications.feed_id,
                        },
                    )
                    await session.delete(existing_classifications)

                updated_classification = ItemFeedLink(
                    item_id=db_item.id, feed_id=output_feed.id
                )
                session.add(updated_classification)
                classified_group_counts[group_name] += 1
                total_classified += 1
            else:
                logger.error(
                    f"Couldn't find item with id {llm_item.id}",
                    extra={"item_id": llm_item.id},
                )
                total_failed += 1

    await session.commit()
```

Does this SQLAlchemy session management work the way I think it does? I am specifically concerned about IntegrityErrors