def authenticate(self, request, **credentials):
        """Only authenticates, does not actually login. See `login`"""
        from allauth.account.auth_backends import AuthenticationBackend

        self.pre_authenticate(request, **credentials)
        AuthenticationBackend.unstash_authenticated_user()
        user = authenticate(request, **credentials)
        alt_user = AuthenticationBackend.unstash_authenticated_user()
        user = user or alt_user
        if user and app_settings.LOGIN_ATTEMPTS_LIMIT:
            cache_key = self._get_login_attempts_cache_key(
                request, **credentials)
            cache.delete(cache_key)
        else:
            self.authentication_failed(request, **credentials)
        return user