code: function getDeepest(collection) {
  	'use strict';
  
  	return collection.sort(function(a, b) {
  		if (axe.utils.contains(a, b)) {
  			return 1;
  		}
  		return -1;
  	})[0];
  }
docs: Get the deepest node in a given collection
  @private
  @param  {Array} collection Array of nodes to test
  @return {Node}             The deepest node