docs: function(args, callback, fallback) {
    /* Get array of objs corresponding to given query.
     *
     * Arguments:
     *  - args:
     *    - query: mongo query, default to {}
     *  - callback(objs): function to be called with result
     *  - fallback(err): function to be called in case of error
     * 
     * */
    var query = args.query || {};
  
    var RestClass = args.RestClass;
    var cache = args.session.cache;
    var awaiting_get_callbacks = args.session.awaiting_get_callbacks;
  
    var key = JSON.stringify(query);
    args.backend.index(RestClass, query, function(objects) {
      objects = objects.map(RestClass.qau);
      callback && callback(objects);
    }, function(error) {
      debug("\nError while index:", error.message);
      debug(error.stack);
      fallback && fallback(error);
    });
  }