function rank() {
		pipeline( opts, done );
		/**
		* Callback invoked after running rank analysis.
		*
		* @private
		* @param {(Error|null)} error - error object
		* @param {ObjectArray} data - query data
		* @param {Object} info - response info
		* @returns {void}
		*/
		function done( error, data, info ) {
			error = error || null;
			data = data || null;
			info = info || null;
			clbk( error, data, info );
		}
	}
Ranks a user's followers.

@private
@returns {void}