def _resolution_to_timedelta(res_text: str) ->str:
    """
    Convert an Entsoe resolution to something that pandas can understand
    """
    resolutions = {'PT60M': '60min', 'P1Y': '12M', 'PT15M': '15min',
        'PT30M': '30min', 'P7D': '7D', 'P1M': '1M'}
    delta = resolutions.get(res_text)
    if delta is None:
        raise NotImplementedError(
            "Sorry, I don't know what to do with the resolution '{}', because there was no documentation to be found of this format. Everything is hard coded. Please open an issue."
            .format(res_text))
    return delta
