def multiplex_user_input(data, cube):
    """
    Get input from the user and ensure it's a multi-dataset dict.

    Parameters
    ----------
    data: Union[pandas.DataFrame, Dict[str, pandas.DataFrame]]
        User input.
    cube: kartothek.core.cube.cube.Cube
        Cube specification.

    Returns
    -------
    pipeline_input: Dict[str, pandas.DataFrame]
        Input for write pipelines.
    """
    if not isinstance(data, dict):
        data = {cube.seed_dataset: data}
    return data