old_contents: # -*- coding: utf-8 -*-
  from __future__ import absolute_import, unicode_literals
  from django_services import admin
  from ..service.maintenance import MaintenanceService
  from ..forms import MaintenanceForm
  import logging
  from django.contrib import messages
  LOG = logging.getLogger(__name__)
  from .. import models
  from django.http import HttpResponseRedirect
  from django.core.urlresolvers import reverse
  
  class MaintenanceAdmin(admin.DjangoServicesAdmin):
      service_class = MaintenanceService
      search_fields = ("scheduled_for", "description", "maximum_workers", 'status')
      list_display = ("scheduled_for", "description", "maximum_workers", 'status')
      fields = ( "description", "scheduled_for", "main_script", "rollback_script",
           "host_query","maximum_workers", "status", "celery_task_id",)
      save_on_top = True
      form = MaintenanceForm
  
      def get_readonly_fields(self, request, obj=None):
          maintenance = obj
          if maintenance:
              if maintenance.celery_task_id:
                  return self.fields
  
          return ('status', 'celery_task_id',)
  
  
      def delete_view(self, request, object_id, extra_context=None):
          maintenance = models.Maintenance.objects.get(id=object_id)
          if maintenance.status ==  maintenance.RUNNING:
              LOG.info("Maintenance: can be deleted!".format(maintenance))
              return super(MaintenanceAdmin, self).delete_view(request,
                  object_id, extra_context)
  
          self.message_user(request, "Task is running and cannot be deleted now. \
              You must wait it to finish", level=messages.ERROR)
  
          LOG.info("Maintenance: can not be deleted!".format(maintenance))
          return HttpResponseRedirect(
              reverse('maintenance:maintenance_maintenance_changelist'))
  
  
new_contents: # -*- coding: utf-8 -*-
  from __future__ import absolute_import, unicode_literals
  from django_services import admin
  from ..service.maintenance import MaintenanceService
  from ..forms import MaintenanceForm
  import logging
  from django.contrib import messages
  LOG = logging.getLogger(__name__)
  from .. import models
  from django.http import HttpResponseRedirect
  from django.core.urlresolvers import reverse
  
  class MaintenanceAdmin(admin.DjangoServicesAdmin):
      service_class = MaintenanceService
      search_fields = ("scheduled_for", "description", "maximum_workers", 'status')
      list_display = ("scheduled_for", "description", "maximum_workers", 'status')
      fields = ( "description", "scheduled_for", "main_script", "rollback_script",
           "host_query","maximum_workers", "status", "celery_task_id",)
      save_on_top = True
      form = MaintenanceForm
  
      def get_readonly_fields(self, request, obj=None):
          maintenance = obj
          if maintenance:
              if maintenance.celery_task_id:
                  return self.fields
  
          return ('status', 'celery_task_id',)
  
  
      def delete_view(self, request, object_id, extra_context=None):
          maintenance = models.Maintenance.objects.get(id=object_id)
          if maintenance.status ==  maintenance.RUNNING:
              self.message_user(request, "Task is running and cannot be deleted now. \
                  You must wait it to finish", level=messages.ERROR)
  
              LOG.info("Maintenance: can not be deleted!".format(maintenance))
              return HttpResponseRedirect(
                  reverse('maintenance:maintenance_maintenance_changelist'))
  
          LOG.info("Maintenance: can be deleted!".format(maintenance))
          return super(MaintenanceAdmin, self).delete_view(request,
              object_id, extra_context)
  
  
  
  
subject: Fix delete_view function