text: """
  Settings for REST framework are all namespaced in the REST_FRAMEWORK setting.
  For example your project's `settings.py` file might look like this:
  
  REST_FRAMEWORK = {
      'DEFAULT_RENDERER_CLASSES': (
          'rest_framework.renderers.JSONRenderer',
          'rest_framework.renderers.YAMLRenderer',
      )
      'DEFAULT_PARSER_CLASSES': (
          'rest_framework.parsers.JSONParser',
          'rest_framework.parsers.YAMLParser',
      )
  }
  
  This module provides the `api_setting` object, that is used to access
  REST framework settings, checking for user settings first, then falling
  back to the defaults.
  """
  from __future__ import unicode_literals
  
  from django.conf import settings
  from django.utils import importlib
  
  from rest_framework import ISO_8601
  from rest_framework.compat import six
  
  
  USER_SETTINGS = getattr(settings, 'REST_FRAMEWORK', None)
  
  DEFAULTS = {
      # Base API policies
      'DEFAULT_RENDERER_CLASSES': (
          'rest_framework.renderers.JSONRenderer',
          'rest_framework.renderers.BrowsableAPIRenderer',
      ),
      'DEFAULT_PARSER_CLASSES': (
          'rest_framework.parsers.JSONParser',
          'rest_framework.parsers.FormParser',
          'rest_framework.parsers.MultiPartParser'
      ),
      'DEFAULT_AUTHENTICATION_CLASSES': (
          'rest_framework.authentication.SessionAuthentication',
          'rest_framework.authentication.BasicAuthentication'
      ),
      'DEFAULT_PERMISSION_CLASSES': (
          'rest_framework.permissions.AllowAny',
      ),
      'DEFAULT_THROTTLE_CLASSES': (
      ),
      'DEFAULT_CONTENT_NEGOTIATION_CLASS':
          'rest_framework.negotiation.DefaultContentNegotiation',
  
      # Genric view behavior
      'DEFAULT_MODEL_SERIALIZER_CLASS':
          'rest_framework.serializers.ModelSerializer',
      'DEFAULT_PAGINATION_SERIALIZER_CLASS':
          'rest_framework.pagination.PaginationSerializer',
      'DEFAULT_FILTER_BACKENDS': (),
  
      # Throttling
      'DEFAULT_THROTTLE_RATES': {
          'user': None,
          'anon': None,
      },
  
      # Pagination
      'PAGINATE_BY': None,
      'PAGINATE_BY_PARAM': None,
      'MAX_PAGINATE_BY': None,
  
      # Authentication
      'UNAUTHENTICATED_USER': 'django.contrib.auth.models.AnonymousUser',
      'UNAUTHENTICATED_TOKEN': None,
  
      # View configuration
      'VIEW_NAME_FUNCTION': 'rest_framework.views.get_view_name',
      'VIEW_DESCRIPTION_FUNCTION': 'rest_framework.views.get_view_description',
  
      # Exception handling
      'EXCEPTION_HANDLER': 'rest_framework.views.exception_handler',
  
      # Testing
      'TEST_REQUEST_RENDERER_CLASSES': (
          'rest_framework.renderers.MultiPartRenderer',
          'rest_framework.renderers.JSONRenderer'
      ),
      'TEST_REQUEST_DEFAULT_FORMAT': 'multipart',
  
      # Browser enhancements
      'FORM_METHOD_OVERRIDE': '_method',
      'FORM_CONTENT_OVERRIDE': '_content',
      'FORM_CONTENTTYPE_OVERRIDE': '_content_type',
      'URL_ACCEPT_OVERRIDE': 'accept',
      'URL_FORMAT_OVERRIDE': 'format',
  
      'FORMAT_SUFFIX_KWARG': 'format',
      'URL_FIELD_NAME': 'url',
  
      # Input and output formats
      'DATE_INPUT_FORMATS': (
          ISO_8601,
      ),
      'DATE_FORMAT': None,
  
      'DATETIME_INPUT_FORMATS': (
          ISO_8601,
      ),
      'DATETIME_FORMAT': None,
  
      'TIME_INPUT_FORMATS': (
          ISO_8601,
      ),
      'TIME_FORMAT': None,
  
      # Pending deprecation
      'FILTER_BACKEND': None,
  }
  
  
  # List of settings that may be in string import notation.
  IMPORT_STRINGS = (
      'DEFAULT_RENDERER_CLASSES',
      'DEFAULT_PARSER_CLASSES',
      'DEFAULT_AUTHENTICATION_CLASSES',
      'DEFAULT_PERMISSION_CLASSES',
      'DEFAULT_THROTTLE_CLASSES',
      'DEFAULT_CONTENT_NEGOTIATION_CLASS',
      'DEFAULT_MODEL_SERIALIZER_CLASS',
      'DEFAULT_PAGINATION_SERIALIZER_CLASS',
      'DEFAULT_FILTER_BACKENDS',
      'EXCEPTION_HANDLER',
      'FILTER_BACKEND',
      'TEST_REQUEST_RENDERER_CLASSES',
      'UNAUTHENTICATED_USER',
      'UNAUTHENTICATED_TOKEN',
      'VIEW_NAME_FUNCTION',
      'VIEW_DESCRIPTION_FUNCTION'
  )
  
  
  def perform_import(val, setting_name):
      """
      If the given setting is a string import notation,
      then perform the necessary import or imports.
      """
      if isinstance(val, six.string_types):
          return import_from_string(val, setting_name)
      elif isinstance(val, (list, tuple)):
          return [import_from_string(item, setting_name) for item in val]
      return val
  
  
  def import_from_string(val, setting_name):
      """
      Attempt to import a class from a string representation.
      """
      try:
          # Nod to tastypie's use of importlib.
          parts = val.split('.')
          module_path, class_name = '.'.join(parts[:-1]), parts[-1]
          module = importlib.import_module(module_path)
          return getattr(module, class_name)
      except ImportError as e:
          msg = "Could not import '%s' for API setting '%s'. %s: %s." % (val, setting_name, e.__class__.__name__, e)
          raise ImportError(msg)
  
  
  class APISettings(object):
      """
      A settings object, that allows API settings to be accessed as properties.
      For example:
  
          from rest_framework.settings import api_settings
          print api_settings.DEFAULT_RENDERER_CLASSES
  
      Any setting with string import paths will be automatically resolved
      and return the class, rather than the string literal.
      """
      def __init__(self, user_settings=None, defaults=None, import_strings=None):
          self.user_settings = user_settings or {}
          self.defaults = defaults or {}
          self.import_strings = import_strings or ()
  
      def __getattr__(self, attr):
          if attr not in self.defaults.keys():
              raise AttributeError("Invalid API setting: '%s'" % attr)
  
          try:
              # Check if present in user settings
              val = self.user_settings[attr]
          except KeyError:
              # Fall back to defaults
              val = self.defaults[attr]
  
          # Coerce import strings into classes
          if val and attr in self.import_strings:
              val = perform_import(val, attr)
  
          self.validate_setting(attr, val)
  
          # Cache the result
          setattr(self, attr, val)
          return val
  
      def validate_setting(self, attr, val):
          if attr == 'FILTER_BACKEND' and val is not None:
              # Make sure we can initialize the class
              val()
  
  api_settings = APISettings(USER_SETTINGS, DEFAULTS, IMPORT_STRINGS)
  