docs: def authenticate(self, request):
          """ Attempt to authenticate the request.
  
          :param request: django.http.Request instance
  
          :return bool: True if success else raises HTTP_401
  
          """
          authenticators = self._meta.authenticators
  
          if request.method == 'OPTIONS' and ADREST_ALLOW_OPTIONS:
              self.auth = AnonimousAuthenticator(self)
              return True
  
          error_message = "Authorization required."
          for authenticator in authenticators:
              auth = authenticator(self)
              try:
                  if not auth.authenticate(request):
                      raise AssertionError(error_message)
  
                  self.auth = auth
                  auth.configure(request)
                  return True
              except AssertionError, e:
                  error_message = str(e)
  
          raise HttpError(error_message, status=status.HTTP_401_UNAUTHORIZED)