function createReducer(orm, updater = defaultUpdater) {
    return (state, action) => {
        const session = orm.session(state || orm.getEmptyState());
        updater(session, action);
        return session.state;
    };
}
Call the returned function to pass actions to Redux-ORM.

@global

@param {ORM} orm - the ORM instance.
@param {Function} [updater] - the function updating the ORM state based on the given action.
@return {Function} reducer that will update the ORM state.