How to use the djangosaml2.views._get_subject_id function in djangosaml2

def logout(self, request, data, binding):
        conf = get_config(request=request)

        state = StateCache(request.session)
        client = Saml2Client(
            conf, state_cache=state, identity_cache=IdentityCache(request.session)
        )

        if 'SAMLResponse' in data:
            # Logout started by us
            client.parse_logout_request_response(data['SAMLResponse'], binding)
            http_response = logout_completed()
        else:
            # Logout started by IdP
            subject_id = _get_subject_id(request.session)
            if subject_id is None:
                http_response = logout_completed()
            else:
                http_info = client.handle_logout_request(
                    data['SAMLRequest'],
                    subject_id,
                    binding,
                    relay_state=data.get('RelayState', ''),
                )
                http_response = HttpResponseRedirect(get_location(http_info))

        state.sync()
        user = request.user
        if user.is_anonymous:
            return http_response
        Token.objects.get(user=user).delete()

def get(self, request):
        state = StateCache(request.session)
        conf = get_config(request=request)

        client = Saml2Client(
            conf, state_cache=state, identity_cache=IdentityCache(request.session)
        )
        subject_id = _get_subject_id(request.session)
        if subject_id is None:
            return logout_failed(_('You cannot be logged out.'))

        try:
            result = client.global_logout(subject_id)
        except KeyError:
            return logout_failed(_('You are not logged in any IdP/AA.'))

        state.sync()
        if not result:
            return logout_failed(_('You are not logged in any IdP/AA.'))

        # Logout is supported only from 1 IdP
        binding, http_info = list(result.values())[0]
        return HttpResponseRedirect(get_location(http_info))