def METHOD_NAME(self) -> None:
    if not self.flight.package.flights:
        # This is theoretically impossible, but for some reason the dialog that owns
        # this object QEditFlightDialog does not dispose properly on close, so this
        # handler may be called for a flight whose package has been canceled, which
        # is an invalid state for calling anything in TotEstimator.
        return
    self.departure_time.setText(f"At T+{self.flight.flight_plan.startup_time()}")
    self.flight_wpt_list.update_list()