code: def viewChanged(self, start, end):
          
          if type(start) == QDate:
              delta           = self._dateStart.daysTo(start)
              self._dateStart = start
              self._dateEnd   = end
              self.adjustChildren(delta)
  
          else:
              delta = self._dateStart.secsTo(start)
              self._dateStart = start.date()
              self._timeStart = start.time()
              
              self._dateEnd = end.date()
              self._timeEnd = end.time()
              
              self.adjustChildren(delta, secs=True)
          
          self.adjustRange()
          
          self.syncDependencies()
          self.syncTree()
docs: Called when the view item is changed by the user.
          
          :param      start | <QDate> || <QDateTime>
                      end   | <QDate> || <QDateTime>