docs: def _cancelScheduledUpgrade(self, justification=None) -> None:
          """
          Cancels scheduled upgrade
  
          :param when: time upgrade was scheduled to
          :param version: version upgrade scheduled for
          """
  
          if self.scheduledAction:
              why_prefix = ": "
              why = justification
              if justification is None:
                  why_prefix = ", "
                  why = "cancellation reason not specified"
  
              ev_data = self.scheduledAction
              logger.info("Cancelling upgrade {}"
                          " of node {}"
                          " of package {}"
                          " to version {}"
                          " scheduled on {}"
                          "{}{}"
                          .format(ev_data.upgrade_id,
                                  self.nodeName,
                                  ev_data.pkg_name,
                                  ev_data.version,
                                  ev_data.when,
                                  why_prefix,
                                  why))
  
              self._unscheduleAction()
              self._actionLog.append_cancelled(ev_data)
              self._notifier.sendMessageUponPoolUpgradeCancel(
                  "Upgrade of package {} on node '{}' to version {} "
                  "has been cancelled due to {}"
                  .format(ev_data.pkg_name, self.nodeName,
                          ev_data.version, why))