src/libs/Bus.js
function unsubscribe(oSubscriber) {
  let nUnsubscribed = 0;
  const oEventsCallbacks = oSubscriber.events;
  if (!oSubscriber || oEventsCallbacks === und) {
    return false;
  }
  iterateObject(oEventsCallbacks, function (oItem, sChannelId) {
    if (oChannels[sChannelId] === und) {
      oChannels[sChannelId] = {};
    }
    nUnsubscribed = _removeSubscribersPerEvent(oItem, sChannelId, oSubscriber);
  });

  return nUnsubscribed > 0;
}
function unsubscribe(oSubscriber) {
  let nUnsubscribed = 0;
  const oEventsCallbacks = oSubscriber.events;
  if (!oSubscriber || oEventsCallbacks === und) {
    return false;
  }
  iterateObject(oEventsCallbacks, function (oItem, sChannelId) {
    if (oChannels[sChannelId] === und) {
      oChannels[sChannelId] = {};
    }
    nUnsubscribed = _removeSubscribersPerEvent(oItem, sChannelId, oSubscriber);
  });

  return nUnsubscribed > 0;
}
unsubscribe gets the oEventsCallbacks methods and removes the handlers of the channel.
@param {Object} oSubscriber
@return {Boolean}