---
id: "M:cAlgo.API.BacktestingDataSources.RemoveAllUnused"
kind: "method"
type: "T:cAlgo.API.BacktestingDataSources"
url: "https://help.ctrader.com/ctrader-algo/references/Plugin/Backtesting/DataSource/BacktestingDataSources/RemoveAllUnused/"
---

> Documentation index for agents: https://help.ctrader.com/ctrader-algo/llms.txt · machine index: https://help.ctrader.com/ctrader-algo/api.json

# BacktestingDataSources.RemoveAllUnused

Member of [BacktestingDataSources](https://help.ctrader.com/ctrader-algo/references/Plugin/Backtesting/DataSource/BacktestingDataSources/index.md).

## RemoveAllUnused()

Removes all previously added backtesting data sources that are not being used.

Environments: Desktop supported · CLI not supported · Cloud not supported.

- CLI: Available to plugins only, and plugins cannot run in the CLI.
- Cloud: Available to plugins only, and plugins cannot run in the cloud.

C#:

```csharp
void RemoveAllUnused()
```

Python:

```python
backtestingDataSources.RemoveAllUnused() -> None
```

Available since cAlgo.API 5.3.

### Examples

C#:

```csharp
protected override void OnStop()
{
    Backtesting.DataSources.RemoveAllUnused();
    Print("Remaining data sources: {0}", Backtesting.DataSources.Count());
}
```

Python:

```python
def on_stop(self):
    api.Backtesting.DataSources.RemoveAllUnused()
    api.Print(f"Remaining data sources: {len(list(api.Backtesting.DataSources))}")
```