The objective is to list the occurrences of vowels in a given word, such that for (word = yellow) and index spits out (e = 1, o = 1)
This (e = 1, o = 1) is not the position/occurrences so I am assuming you want to count the number of times each vowel occurs.
if letters in vowels:
if letters not in count:
count[letters]=0 ## add to dictionary, initialize counter to zero
count[letters] += 1 ## add one to a counter