PYTHON 3.6: Write a function named initialLetters that takes one parameter, wordList -- a list of words. Create and return a dictionary in which each initial letter of a word in wordList is a key and the corresponding value is a list of the words in wordList that begin with that letter. There should be no duplicate words in any value in the dictionary.

For example, the following is correct output:

horton = ['I', 'say', 'what', 'I', 'mean', 'and', 'I', 'mean', 'what', 'I', 'say']

print(initialLetters(horton))

{'I': ['I'], 's': ['say'], 'w': ['what'], 'm': ['mean'], 'a': ['and']}