Shifts the children for this item by the inputed number of days.
        
        :param      delta | <int>

def adjustChildren(self, delta, secs=False):
        """
        Shifts the children for this item by the inputed number of days.
        
        :param      delta | <int>
        """
        if self.adjustmentsBlocked('children'):
            return
            
        if self.itemStyle() != self.ItemStyle.Group:
            return
        
        if not delta:
            return
        
        for c in range(self.childCount()):
            child = self.child(c)
            child.blockAdjustments('range', True)
            if secs:
                dstart = child.dateTimeStart()
                dstart = dstart.addSecs(delta)
                child.setDateStart(dstart.date())
                child.setTimeStart(dstart.time())
            else:
                child.setDateStart(child.dateStart().addDays(delta))
            child.blockAdjustments('range', False)