code: function isCapped(coll, options, callback) {
    optionsOp(coll, options, (err, document) => {
      if (err) return handleCallback(callback, err);
      handleCallback(callback, null, !!(document && document.capped));
    });
  }
docs: Determine whether the collection is a capped collection.
  
  @method
  @param {Collection} a Collection instance.
  @param {Object} [options] Optional settings. See Collection.prototype.isCapped for a list of options.
  @param {Collection~resultCallback} [callback] The results callback