new_contents: from django.conf import settings
  from django.core.exceptions import ImproperlyConfigured
  from django.utils.importlib import import_module
  
  def get_backend():
      """
      Return an instance of the registration backend for use on this
      site, as determined by the ``REGISTRATION_BACKEND`` setting. Raise
      ``django.core.exceptions.ImproperlyConfigured`` if the specified
      backend cannot be located.
      
      """
      i = settings.REGISTRATION_BACKEND.rfind('.')
      module, attr = settings.REGISTRATION_BACKEND[:i], settings.REGISTRATION_BACKEND[i+1:]
      try:
          mod = import_module(module)
      except ImportError, e:
          raise ImproperlyConfigured('Error loading registration backend %s: "%s"' % (module, e))
      try:
          backend_class = getattr(mod, attr)
      except AttributeError:
          raise ImproperlyConfigured('Module "%s" does not define a registration backend named "%s"' % (module, attr))
      return backend_class()
  
subject: Add utility function for retrieving the active registration backend.