def __init__(self, *args, **kwargs):
        self.last_stat = get_stat(self.statistics_type)
        self.last_time = time()
        self.last_interface = None
        self.value_format = "{value:%s.%sf} {unit}" % (self.left_align, self.precision)
        self.units = ["kb", "mb", "gb", "tb", ]  # list of units, first one - value/initial_multi, second - value/1024, third - value/1024^2, etc...
Format of total, up and down placeholders under FORMAT.
dataset/ETHPy150Open ultrabug/py3status/py3status/modules/vnstat.py/Py3status.__init__