Adds the period filter to the filters list.
        :param request: Current request.
        :return: Iterable of filters.

def get_list_filter(self, request):
        """
        Adds the period filter to the filters list.
        :param request: Current request.
        :return: Iterable of filters.
        """

        original = super(TrackedLiveAdmin, self).get_list_filter(request)
        return original + type(original)([PeriodFilter])