code: function updateClasses(clearContainerCache, contexts) {
  
  	if (clearContainerCache || !containerCache) {
  		containerCache = createCacheMap();
  	}
  
  	if (!Object.keys(queries).length) {
  		return;
  	}
  
  	var elementsTree = buildElementsTree(contexts);
  
  	while(updateClassesRead(elementsTree)) {
  		updateClassesWrite(elementsTree);
  	}
  	updateClassesWrite(elementsTree);
  
  }
docs: Step 3: Loop through the `queries` and add or remove the CSS classes of all
  matching elements
  
  @param {boolean}         clearContainerCache
  @param {Array.<Element>} contexts