text: from django.utils.translation import ugettext_lazy as _
  from django.db import models
  from django.contrib.auth import models as auth_models
  
  class Clipboard(models.Model):
      user = models.ForeignKey(auth_models.User, related_name="filer_clipboards")
      files = models.ManyToManyField('File', related_name="in_clipboards", through='ClipboardItem')
      
      def append_file(self, file):
          newitem = ClipboardItem(file=file, clipboard=self)
          newitem.save()
      
      def empty(self):
          for item in self.bucket_items.all():
              item.delete()
      empty.alters_data = True
      
      
      def __unicode__(self):
          return u"Clipboard %s of %s" % (self.id, self.user)
      class Meta:
          app_label = 'filer'
          verbose_name = _('Clipboard')
  
  class ClipboardItem(models.Model):
      file = models.ForeignKey('File')
      clipboard = models.ForeignKey(Clipboard)
      class Meta:
          app_label = 'filer'
          verbose_name = _('Clipboard item')
          verbose_name_plural = _('Clipboard items')