old_contents: from django.contrib import admin
  from simple_history.admin import SimpleHistoryAdmin
  from .models import (
      Contact,
      ContactField,
      Tag,
      Book,
      BookOwner,
      LogEntry,
  )
  
  class ContactAdmin(SimpleHistoryAdmin):
      list_display = (
          'name',
          'book',
          'created',
          'changed'
      )
  
  class TagAdmin(SimpleHistoryAdmin):
      list_display = (
          'tag',
          'book',
          'created',
          'changed',
      )
  
  
  class ContactFieldAdmin(SimpleHistoryAdmin):
      list_display = (
          'value',
          'kind',
          'contact',
          'created',
          'changed',
          'preferred',
      )
  
  
  class LogAdmin(SimpleHistoryAdmin):
      list_display = (
          'contact',
          'kind',
          'created',
          'time',
      )
  
  admin.site.register(Contact, ContactAdmin)
  admin.site.register(Tag, TagAdmin)
  admin.site.register(Book, SimpleHistoryAdmin)
  admin.site.register(BookOwner, SimpleHistoryAdmin)
  admin.site.register(LogEntry, LogAdmin)
  admin.site.register(ContactField, ContactFieldAdmin)
  
new_contents: from django.contrib import admin
  from simple_history.admin import SimpleHistoryAdmin
  from .models import (
      Contact,
      ContactField,
      Tag,
      Book,
      BookOwner,
      LogEntry,
  )
  
  class ContactAdmin(SimpleHistoryAdmin):
      list_display = (
          'name',
          'book',
          'last_contact',
          'created',
          'changed'
      )
  
  class TagAdmin(SimpleHistoryAdmin):
      list_display = (
          'tag',
          'book',
          'created',
          'changed',
      )
  
  
  class ContactFieldAdmin(SimpleHistoryAdmin):
      list_display = (
          'value',
          'kind',
          'contact',
          'created',
          'changed',
          'preferred',
      )
  
  
  class LogAdmin(SimpleHistoryAdmin):
      list_display = (
          'contact',
          'kind',
          'created',
          'time',
      )
  
  admin.site.register(Contact, ContactAdmin)
  admin.site.register(Tag, TagAdmin)
  admin.site.register(Book, SimpleHistoryAdmin)
  admin.site.register(BookOwner, SimpleHistoryAdmin)
  admin.site.register(LogEntry, LogAdmin)
  admin.site.register(ContactField, ContactFieldAdmin)
  
subject: Add 'last_contact' to contact admin