Write a program that reads in the text file attached, converts all words to lowercase, and prints out all words in the file that begin with that key letter a, the letter b, and so on. Build a dictionary whose keys are the lowercase letters, and whose values are sets of words which begin with that key letter. After processing the data, print the dictionary to the screen in alphabetical order aligned in two fixed sized columns. Such as: a - {'add', 'alpha', 'at'} b - {'both', 'but', 'box'} Do not add duplicate words to the dictionary.