old_contents: from django.contrib import admin
  
  from .models import Maintenance, MaintenanceType, Software, SysAdmin, System
  
  
  admin.site.register(Maintenance)
  admin.site.register(MaintenanceType)
  admin.site.register(Software)
  admin.site.register(SysAdmin)
  admin.site.register(System)
  
new_contents: from django.contrib import admin
  
  from .models import Maintenance, MaintenanceType, Software, SysAdmin, System
  
  
  @admin.register(Maintenance)
  class MaintenanceAdmin(admin.ModelAdmin):
  
      fieldset_basic = ('Basic', {
          'fields': [
              'system',
              'sys_admin',
              'maintenance_type',
              'software',
              'datetime',
              'success',
          ],
      })
  
      fieldset_description = ('Description', {
          'fields': [
              'description',
              'description_markup_type',
          ],
      })
  
      fieldset_procedure = ('Procedure', {
          'fields': [
              'procedure',
              'procedure_markup_type',
          ],
      })
  
      fieldset_problems = ('Problems', {
          'fields': [
              'problems',
              'problems_markup_type',
          ],
      })
  
      fieldsets = [
          fieldset_basic,
          fieldset_description,
          fieldset_procedure,
          fieldset_problems,
      ]
  
      filter_horizontal = ['software']
  
      list_display = [
          'id',
          'system',
          'datetime',
          'maintenance_type',
          'sys_admin',
          'success',
      ]
  
      list_filter = [
          'system',
          'maintenance_type',
          'software',
          'success',
          'sys_admin',
      ]
  
      search_fields = [
          'description',
          'procedure',
          'problems',
      ]
  
  
  admin.site.register(MaintenanceType)
  admin.site.register(Software)
  admin.site.register(SysAdmin)
  admin.site.register(System)
  
subject: Add detailed Maintenance admin