<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def is_escalable(self, notification, escalations, timeperiods):
 """Check if a notification can be escalated. Basically call is_eligible for each escalation :param notification: notification we would like to escalate :type notification: alignak.objects.notification.Notification :param escalations: Esclations objects, used to get escalation objects (period) :type escalations: alignak.objects.escalation.Escalations :param timeperiods: Timeperiods objects, used to get escalation period :type timeperiods: alignak.objects.timeperiod.Timeperiods :return: True if notification can be escalated, otherwise False :rtype: bool """

        cls = self.__class__

        # We search since when we are in notification for escalations
        # that are based on time
        in_notif_time = time.time() - notification.creation_time

        # Check is an escalation match the current_notification_number
        for escalation_id in self.escalations:
            escalation = escalations[escalation_id]
            escalation_period = timeperiods[escalation.escalation_period]
            if escalation.is_eligible(notification.t_to_go, self.state, notification.notif_nb,
                                      in_notif_time, cls.interval_length, escalation_period):
                return True

        return False