def METHOD_NAME(self, value):
    dt = datetime.utcfromtimestamp(value)
    if self.tz() is not None:
        dt = pytz.utc.localize(dt)
        dt = dt.astimezone(self.tz())
        return dt.strftime("%Y%m%dT%H%M%S")
    return None  # for the moment I prefer not to display anything instead of something wrong