def temporal_filter(start_date, end_date=None):
    """TemporalFilter data model.

    Parameters
    ----------
    start_date : str
        ISO 8601 formatted date.
    end_date : str, optional
        ISO 8601 formatted date.
    
    Returns
    -------
    temporal_filter : dict
        TemporalFilter data model as a dictionnary.
    """
    if not end_date:
        end_date = start_date
    return {
        'startDate': start_date,
        'endDate': end_date
    }