old_contents: from django.contrib import admin
  from . import models
  
  
  class LaneAdmin(admin.ModelAdmin):
      list_filter = ('cluster__name',)
  
  admin.site.register(models.Lane, LaneAdmin)
  
  admin.site.register(models.LaneReservation)
  
  admin.site.register(models.LaneFullTimeValidator)
  admin.site.register(models.LaneTimeIntervalValidator)
  admin.site.register(models.LaneNotWithinPeriodValidator)
  admin.site.register(models.LaneWithinPeriodValidator)
  
new_contents: from django.contrib import admin
  from . import models
  
  
  class LaneAdmin(admin.ModelAdmin):
      list_filter = ('cluster__name',)
  
  admin.site.register(models.Lane, LaneAdmin)
  
  admin.site.register(models.LaneReservation)
  
  admin.site.register(models.LaneFullTimeValidator)
  admin.site.register(models.LaneGivenHoursAndWeekdaysValidator)
  admin.site.register(models.LaneTimeIntervalValidator)
  admin.site.register(models.LaneNotWithinPeriodValidator)
  admin.site.register(models.LaneMaxReservationsPerUserValidator)
  
  
  class PeriodInline(admin.TabularInline):
      model = models.Period
  
  
  class WithinPeriodValidatorAdmin(admin.ModelAdmin):
      inlines = [PeriodInline]
  
  
  admin.site.register(models.LaneWithinPeriodValidator, WithinPeriodValidatorAdmin)
  
subject: enhance admin for validators