':type s: str
:rtype: str'

def reverseVowels(self, s):

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