text: from __future__ import unicode_literals
  
  from django.conf import settings
  from django.contrib.admin.utils import quote
  from django.contrib.contenttypes.models import ContentType
  from django.db import models
  from django.urls import NoReverseMatch, reverse
  from django.utils import timezone
  from django.utils.encoding import python_2_unicode_compatible, smart_text
  from django.utils.translation import ugettext, ugettext_lazy as _
  
  ADDITION = 1
  CHANGE = 2
  DELETION = 3
  
  
  class LogEntryManager(models.Manager):
      use_in_migrations = True
  
      def log_action(self, user_id, content_type_id, object_id, object_repr, action_flag, change_message=''):
          self.model.objects.create(
              user_id=user_id,
              content_type_id=content_type_id,
              object_id=smart_text(object_id),
              object_repr=object_repr[:200],
              action_flag=action_flag,
              change_message=change_message,
          )
  
  
  @python_2_unicode_compatible
  class LogEntry(models.Model):
      action_time = models.DateTimeField(
          _('action time'),
          default=timezone.now,
          editable=False,
      )
      user = models.ForeignKey(
          settings.AUTH_USER_MODEL,
          models.CASCADE,
          verbose_name=_('user'),
      )
      content_type = models.ForeignKey(
          ContentType,
          models.SET_NULL,
          verbose_name=_('content type'),
          blank=True, null=True,
      )
      object_id = models.TextField(_('object id'), blank=True, null=True)
      # Translators: 'repr' means representation (https://docs.python.org/3/library/functions.html#repr)
      object_repr = models.CharField(_('object repr'), max_length=200)
      action_flag = models.PositiveSmallIntegerField(_('action flag'))
      change_message = models.TextField(_('change message'), blank=True)
  
      objects = LogEntryManager()
  
      class Meta:
          verbose_name = _('log entry')
          verbose_name_plural = _('log entries')
          db_table = 'django_admin_log'
          ordering = ('-action_time',)
  
      def __repr__(self):
          return smart_text(self.action_time)
  
      def __str__(self):
          if self.is_addition():
              return ugettext('Added "%(object)s".') % {'object': self.object_repr}
          elif self.is_change():
              return ugettext('Changed "%(object)s" - %(changes)s') % {
                  'object': self.object_repr,
                  'changes': self.change_message,
              }
          elif self.is_deletion():
              return ugettext('Deleted "%(object)s."') % {'object': self.object_repr}
  
          return ugettext('LogEntry Object')
  
      def is_addition(self):
          return self.action_flag == ADDITION
  
      def is_change(self):
          return self.action_flag == CHANGE
  
      def is_deletion(self):
          return self.action_flag == DELETION
  
      def get_edited_object(self):
          "Returns the edited object represented by this log entry"
          return self.content_type.get_object_for_this_type(pk=self.object_id)
  
      def get_admin_url(self):
          """
          Returns the admin URL to edit the object represented by this log entry.
          """
          if self.content_type and self.object_id:
              url_name = 'admin:%s_%s_change' % (self.content_type.app_label, self.content_type.model)
              try:
                  return reverse(url_name, args=(quote(self.object_id),))
              except NoReverseMatch:
                  pass
          return None
  