indices - Appending Vowel Location Python -

i trying figure out why getting empty list when code ran. goal take string, find index of vowels , append index list. index starting @ 1 instead of zero. tips error might occurring great! if there general oversight notice please let me know. relatively new python.

def vowel_indices(word):     vowels = ["a", "e", "i", "o", "u"]     vowel_idx = []     word.lower()      idx, letter in enumerate(word, start = 1):         if letter == vowels:             vowel_idx.append(idx)          return vowel_idx      

if letter == vowels: should if letter in vowels:

vowels list , string can never equal list , should move return out of loop stop function in it's track first time loops through