code: function processCssomAssets(nestedAssets) {
  	const result = [];
  
  	nestedAssets.forEach(item => {
  		if (Array.isArray(item)) {
  			result.push(...processCssomAssets(item));
  		} else {
  			result.push(item);
  		}
  	});
  
  	return result;
  }
docs: Process results from `loadCssom` queues of all root nodes
  NOTE:
  using `axe.utils.queue` from various `loadCssom` paths, returns a nested array of arrays at various depths,
  hence the need to flatten arrays
  
  @param {Array<Object>} assets CSSOM assets for each root
  @returns {Object} CSSOM object