old_contents: from django.apps import AppConfig
  from django.db.models import signals
  
  from nodeconductor.cost_tracking import CostTrackingRegister
  from nodeconductor.template import TemplateRegistry
  
  
  class SaltStackConfig(AppConfig):
      name = 'nodeconductor_saltstack.exchange'
      verbose_name = "NodeConductor SaltStack Exchange"
      service_name = 'SaltStack'
  
      def ready(self):
          from .cost_tracking import SaltStackCostTrackingBackend
          CostTrackingRegister.register(self.label, SaltStackCostTrackingBackend)
  
          # template
          from .template import TenantProvisionTemplateForm
          TemplateRegistry.register(TenantProvisionTemplateForm)
  
          # import it here in order to register as SaltStack backend
          from .backend import ExchangeBackend
  
          from . import handlers
          from ..saltstack.models import SaltStackServiceProjectLink
  
          ExchangeTenant = self.get_model('ExchangeTenant')
          User = self.get_model('User')
  
          signals.post_save.connect(
              handlers.init_exchange_storage_limit,
              sender=SaltStackServiceProjectLink,
              dispatch_uid='nodeconductor_saltstack.exchange.handlers.init_exchange_storage_limit',
          )
  
          # Tenants CRUD
          signals.post_save.connect(
              handlers.increase_quotas_usage_on_tenant_creation,
              sender=ExchangeTenant,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.increase_quotas_usage_on_tenant_creation',
          )
  
          signals.post_delete.connect(
              handlers.decrease_quotas_usage_on_tenant_deletion,
              sender=ExchangeTenant,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.decrease_quotas_usage_on_tenant_deletion',
          )
  
          # Users CRUD
          signals.post_save.connect(
              handlers.increase_tenant_quotas_usage_on_user_creation_or_modification,
              sender=User,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.increase_tenant_quotas_usage_on_user_creation_or_modification',
          )
  
          signals.post_delete.connect(
              handlers.decrease_tenant_quotas_usage_on_user_deletion,
              sender=User,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.decrease_tenant_quotas_usage_on_user_deletion',
          )
  
new_contents: from django.apps import AppConfig
  from django.db.models import signals
  
  from nodeconductor.cost_tracking import CostTrackingRegister
  from nodeconductor.template import TemplateRegistry
  
  
  class SaltStackConfig(AppConfig):
      name = 'nodeconductor_saltstack.exchange'
      verbose_name = "NodeConductor SaltStack Exchange"
      service_name = 'SaltStack'
  
      def ready(self):
          from .cost_tracking import SaltStackCostTrackingBackend
          CostTrackingRegister.register(self.label, SaltStackCostTrackingBackend)
  
          # template
          from .template import TenantProvisionTemplateForm
          TemplateRegistry.register(TenantProvisionTemplateForm)
  
          # import it here in order to register as SaltStack backend
          from .backend import ExchangeBackend
  
          from . import handlers
          from ..saltstack.models import SaltStackServiceProjectLink
  
          ExchangeTenant = self.get_model('ExchangeTenant')
          User = self.get_model('User')
  
          signals.post_save.connect(
              handlers.init_exchange_storage_limit,
              sender=SaltStackServiceProjectLink,
              dispatch_uid='nodeconductor_saltstack.exchange.handlers.init_exchange_storage_limit',
          )
  
          # Tenants CRUD
          signals.post_save.connect(
              handlers.increase_quotas_usage_on_tenant_creation,
              sender=ExchangeTenant,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.increase_quotas_usage_on_tenant_creation',
          )
  
          signals.post_save.connect(
              handlers.init_quotas_on_tenant_creation,
              sender=ExchangeTenant,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.init_quotas_on_tenant_creation',
          )
  
          signals.post_delete.connect(
              handlers.decrease_quotas_usage_on_tenant_deletion,
              sender=ExchangeTenant,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.decrease_quotas_usage_on_tenant_deletion',
          )
  
          # Users CRUD
          signals.post_save.connect(
              handlers.increase_tenant_quotas_usage_on_user_creation_or_modification,
              sender=User,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.increase_tenant_quotas_usage_on_user_creation_or_modification',
          )
  
          signals.post_delete.connect(
              handlers.decrease_tenant_quotas_usage_on_user_deletion,
              sender=User,
              dispatch_uid='nodeconductor.saltstack.exchange.handlers.decrease_tenant_quotas_usage_on_user_deletion',
          )
  
subject: Add missing handler registration