docs: function(err) {
  		/**
  		 * If err is an Error object, break the chain and call catch
  		 */
  		if (err && (err.constructor.name === "Error" || err.constructor.name === "TypeError") && this.onCatch) {
  			this.onCatch(err);
  			return;
  		}
  
  		var nextFn = this.fnStack.shift();
  		if (nextFn) {
  			/**
  			 * Ensure arguments are passed as an Array
  			 */
  			var args = Array.prototype.slice.call(arguments);
  			return this.execute(nextFn.fn, args);
  		}
  	}