> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fiddler.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# ItemIdCollision

> Raised when `insert()` names an item id that already exists with different content, or that changed while the call was in flight.

Inserting only adds items; nothing was written. Re-read the items, which may
already hold this content, or replace them with `update_items()`.
`item_ids` holds the items the server names, and `server_message` the
server's own wording.

**New in version 0.8.0**

## Example

```python theme={null}
from fiddler_evals.exceptions import ItemIdCollision

try:
    dataset.insert(items)
except ItemIdCollision as e:
    print(f"Already in the dataset: {e.item_ids}")
```

## message

**Type:** `str`

**Value:** `'An inserted item id already exists with different content, or changed while the call was in flight'`

Human-readable error message; this class default is used when none is given.