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# data\_designer.config.custom\_column

User-facing utilities for custom column generation.

## Module Contents

### Functions

| Name                                                                                            | Description                                                                |
| ----------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------- |
| [`validate_generator_signature`](#data_designerconfigcustom_columnvalidate_generator_signature) | Validate generator function signature. Returns positional params if valid. |
| [`custom_column_generator`](#data_designerconfigcustom_columncustom_column_generator)           | Decorator to define metadata for a custom column generator function.       |

### Data

[`F`](#data_designerconfigcustom_columnf)
[`EXPECTED_PARAMS`](#data_designerconfigcustom_columnexpected_params)

### API

```python
F = TypeVar(...)
```

```python
EXPECTED_PARAMS = ()
```

```python
data_designer.config.custom_column.validate_generator_signature(fn: typing.Callable[..., typing.Any]) -> list[inspect.Parameter]
```

Validate generator function signature. Returns positional params if valid.

```python
data_designer.config.custom_column.custom_column_generator(
    required_columns: list[str] | None = None,
    side_effect_columns: list[str] | None = None,
    model_aliases: list[str] | None = None
) -> typing.Callable[[data_designer.config.custom_column.F], data_designer.config.custom_column.F]
```

Decorator to define metadata for a custom column generator function.

**Parameters:**

Columns that must exist before this column runs (DAG ordering).

Additional columns the function will create.

Model aliases to include in the `models` dict (required for LLM access).