old_contents: from django.contrib import admin
  from django.contrib.contenttypes.admin import GenericTabularInline
  from .models import (Location, Permanence, Equipment, Lending, Position,
                      MembershipType, Membership, PublicFile, PublicImage,
                      ProtectedFile, ProtectedImage, AdminFile, AdminImage)
  
  class AdminFileInline(GenericTabularInline):
      model = AdminFile
  
  class AdminImageInline(GenericTabularInline):
      model = AdminImage
  
  class ProtectedFileInline(GenericTabularInline):
      model = ProtectedFile
  
  class ProtectedImageInline(GenericTabularInline):
      model = ProtectedImage
  
  class PublicFileInline(GenericTabularInline):
      model = PublicFile
  
  class PublicImageInline(GenericTabularInline):
      model = PublicImage
  
  class MembershipInline(admin.StackedInline):
      model = Membership
      extra = 0
  
  @admin.register(MembershipType)
  class MembershipTypeAdmin(admin.ModelAdmin):
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  @admin.register(Position)
  class PositionAdmin(admin.ModelAdmin):
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  admin.site.register(Location)
  admin.site.register(Permanence)
  admin.site.register(Equipment)
  admin.site.register(Lending)
  admin.site.register(PublicFile)
  admin.site.register(PublicImage)
  
new_contents: from django.contrib import admin
  from django.contrib.contenttypes.admin import GenericTabularInline
  from .models import (Location, Permanence, Equipment, Lending, Position,
                      MembershipType, Membership, PublicFile, PublicImage,
                      ProtectedFile, ProtectedImage, AdminFile, AdminImage)
  
  class AdminFileInline(GenericTabularInline):
      model = AdminFile
  
  class AdminImageInline(GenericTabularInline):
      model = AdminImage
  
  class ProtectedFileInline(GenericTabularInline):
      model = ProtectedFile
  
  class ProtectedImageInline(GenericTabularInline):
      model = ProtectedImage
  
  class PublicFileInline(GenericTabularInline):
      model = PublicFile
  
  class PublicImageInline(GenericTabularInline):
      model = PublicImage
  
  class MembershipInline(admin.StackedInline):
      model = Membership
      extra = 0
  
  @admin.register(MembershipType)
  class MembershipTypeAdmin(admin.ModelAdmin):
  
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  @admin.register(Position)
  class PositionAdmin(admin.ModelAdmin):
      class Media:
          js = ('tinymce/tinymce.min.js', 'js/tinymce_4_config.js')
  
  admin.site.register(Location)
  admin.site.register(Permanence)
  admin.site.register(Equipment)
  admin.site.register(Lending)
  admin.site.register(PublicFile)
  admin.site.register(PublicImage)
  admin.site.register(ProtectedFile)
  admin.site.register(ProtectedImage)
  admin.site.register(AdminFile)
  admin.site.register(AdminImage)
  
subject: Add ProtectedFile, ProtectedImage, AdminFile and AdminImage.