'Return redirect url'

def auth_url(self):

    if (self.STATE_PARAMETER or self.REDIRECT_STATE):
        name = (self.AUTH_BACKEND.name + '_state')
        state = (self.request.session.get(name) or self.state_token())
        self.request.session[(self.AUTH_BACKEND.name + '_state')] = state
    else:
        state = None
    params = self.auth_params(state)
    params.update(self.get_scope_argument())
    params.update(self.auth_extra_arguments())
    if self.request.META.get('QUERY_STRING'):
        query_string = ('&' + self.request.META['QUERY_STRING'])
    else:
        query_string = ''
    return (((self.AUTHORIZATION_URL + '?') + urlencode(params)) + query_string)
