old_contents: 
  from django.apps import apps, AppConfig
  from django.utils.translation import ugettext_lazy as _
  from django.utils.functional import cached_property
  from django.conf import settings
  
  
  default_app_config = 'site_config.SiteConfigApp'
  
  __version__ = '2.0'
  
  __all__ = ['config', 'default_app_config', 'SiteConfig', 'get_config_for_site']
  
  
  class SiteConfigApp(AppConfig):
      name = 'site_config'
      verbose_name = _("Settings")
  
  
  class SiteConfig(object):
  
      def __init__(self, site_id):
          self._site_id = site_id
  
      def __getattr__(self, name):
          if name.startswith('_'):
              return super(SiteConfig, self).__getattribute__(name)
  
          return self._get_field(name).value
  
      def __setattr__(self, key, value):
          if key.startswith('_'):
              super(SiteConfig, self).__setattr__(key, value)
          else:
              self._get_field(key).value = value
  
      @cached_property
      def _fields(self):
          field_model = apps.get_model('site_config', 'ConfigField')
          fields = field_model.objects.filter(site_id=self._site_id)
          return {f.name: f for f in fields}
  
      def _get_field(self, name):
          try:
              return self._fields[name]
          except KeyError:
              raise AttributeError("Site config has no field named '%s'" % name)
  
  
  config = SiteConfig(settings.SITE_ID)
  
  
  def get_config_for_site(request=None):
  
      if request:
          host = request.META.get('HTTP_HOST')
          site_model = apps.get_model('sites', 'Site')
  
          try:
              site = site_model.objects.get(domain=host)
              return SiteConfig(site.id)
          except site_model.DoesNotExist:
              pass
  
      return config
  
new_contents: 
  from django.apps import apps, AppConfig
  from django.utils.translation import ugettext_lazy as _
  from django.utils.functional import cached_property
  from django.conf import settings
  
  
  default_app_config = 'site_config.SiteConfigApp'
  
  __version__ = '2.0'
  
  __all__ = ['default_app_config', 'SiteConfig', 'get_config_for_site']
  
  
  class SiteConfigApp(AppConfig):
      name = 'site_config'
      verbose_name = _("Settings")
  
  
  class SiteConfig(object):
  
      def __init__(self, site_id):
          self._site_id = site_id
  
      def __getattr__(self, name):
          if name.startswith('_'):
              return super(SiteConfig, self).__getattribute__(name)
  
          return self._get_field(name).value
  
      def __setattr__(self, key, value):
          if key.startswith('_'):
              super(SiteConfig, self).__setattr__(key, value)
          else:
              self._get_field(key).value = value
  
      @cached_property
      def _fields(self):
          field_model = apps.get_model('site_config', 'ConfigField')
          fields = field_model.objects.filter(site_id=self._site_id)
          return {f.name: f for f in fields}
  
      def _get_field(self, name):
          try:
              return self._fields[name]
          except KeyError:
              raise AttributeError("Site config has no field named '%s'" % name)
  
  
  def get_config_for_site(request=None):
  
      if request:
          host = request.META.get('HTTP_HOST')
          site_model = apps.get_model('sites', 'Site')
  
          try:
              site = site_model.objects.get(domain=host)
              return SiteConfig(site.id)
          except site_model.DoesNotExist:
              pass
  
      return SiteConfig(settings.SITE_ID)
  
subject: Fix upload bug.