Use Python programming to count all unique words for all files in a given directory. The output must be words and their corresponding frequency. Note: • To get all files under a directory, use os.listdir(directory name) • To check if a character is an alpha character, you can use the following example expression (3 is not a word character): o >>> str = "hello3hello" o >>> str = str.lower() # to be all lowercase first o >>> str[5] > ‘a’ and str[5] < ‘z’ o >>> False • To debug your code, please create a folder with at least 3 text files. You don’t need to submit your example folder and text files.