Retrieves data from eDNA history for a given tag. The data will be
    averaged over the specified "period".

    :param tag_name: fully-qualified (site.service.tag) eDNA tag
    :param start_time: must be in format mm/dd/yy hh:mm:ss
    :param end_time: must be in format mm/dd/yy hh:mm:ss
    :param period: in units of seconds (e.g. 10)
    :param desc_as_label: use the tag description as the column name instead
        of the full tag
    :param label: supply a custom label to use as the DataFrame column name
    :return: a pandas DataFrame with timestamp, value, and status

def GetHistAvg(tag_name, start_time, end_time, period,
               desc_as_label=False, label=None):
    """
    Retrieves data from eDNA history for a given tag. The data will be
    averaged over the specified "period".

    :param tag_name: fully-qualified (site.service.tag) eDNA tag
    :param start_time: must be in format mm/dd/yy hh:mm:ss
    :param end_time: must be in format mm/dd/yy hh:mm:ss
    :param period: in units of seconds (e.g. 10)
    :param desc_as_label: use the tag description as the column name instead
        of the full tag
    :param label: supply a custom label to use as the DataFrame column name
    :return: a pandas DataFrame with timestamp, value, and status
    """
    return GetHist(tag_name, start_time, end_time, mode="avg", period=period,
                   desc_as_label=desc_as_label, label=label)