code: def mark_deactivated(self,request,queryset):
          
          rows_updated = queryset.update(Active=False, End=datetime.date.today() )
          if rows_updated == 1:
              message_bit = "1 cage was"
          else:
              message_bit = "%s cages were" % rows_updated
          self.message_user(request, "%s successfully marked as deactivated." % message_bit)
docs: An admin action for marking several cages as inactive.
  		
          This action sets the selected cages as Active=False and Death=today.
          This admin action also shows as the output the number of mice sacrificed.