code: function getRegexFromDoubleArray( twoPartTransitionWords ) {
  	const cacheKey = flattenDeep( twoPartTransitionWords ).join( "" );
  	if ( regexFromDoubleArrayCacheKey !== cacheKey || regexFromDoubleArray === null ) {
  		regexFromDoubleArrayCacheKey = cacheKey;
  		regexFromDoubleArray = createRegexFromDoubleArray( twoPartTransitionWords );
  	}
  	return regexFromDoubleArray;
  }
docs: Memoizes the createRegexFromDoubleArray with the twoPartTransitionWords.
  
  @param {Array} twoPartTransitionWords The array containing two-part transition words.
  
  @returns {RegExp} The RegExp to match text with a double array.