How to use the pouchdb-mapreduce-utils.promisedCallback function in pouchdb-mapreduce-utils

function abstractQuery(fun, opts, callback) {
    var db = this;
    if (typeof opts === 'function') {
      callback = opts;
      opts = {};
    }
    opts = opts ? coerceOptions(opts) : {};

    if (typeof fun === 'function') {
      fun = {map : fun};
    }

    var promise = Promise.resolve().then(function () {
      return queryPromised(db, fun, opts);
    });
    promisedCallback(promise, callback);
    return promise;
  }