def METHOD_NAME(attribute_name: str = "report_date") -> str:
    """Return the report date requested as query parameter if it's in the past, else return an empty string."""
    if report_date_string := dict(bottle.request.query).get(attribute_name):
        iso_report_date_string = str(report_date_string).replace("Z", "+00:00")
        if iso_report_date_string < iso_timestamp():
            return iso_report_date_string
    return ""