fetchPage(options) {
      if (!options) options = {};
      return Helpers.fetchPage.call(this, options);
    }
@event Collection#fetched
@tutorial events

@description
Fired after a `fetch` operation. A promise may be returned from the
event handler for async behaviour.

@param {Collection} collection The collection performing the {@link Collection#fetch}.
@param {Object} response Knex query response.
@param {Object} options Options object passed to {@link Collection#fetch fetch}.
@returns {Promise}