Leetcode345.reverse vowels of a string

def reverseVowels(s):
    vowels = 'aeiou'
    string = list(s)
    left, right = 0, len(s) - 1
    while left < right:
        if string[left].lower() not in vowels:
            left += 1
        elif string[right].lower() not in vowels:
            right -= 1
        else:
            string[left], string[right] = string[right], string[left]
            left += 1
            right -= 1
    return ''.join(string)