Function in Python that counts the number of vowels in a string

vowels = []

def vowelscount(string):

    if "a" in string:

        vowels.append("a")

    if "e" in string:

        vowels.append("e")

    if "i" in string:

        vowels.append("i")

    if "o" in string:

        vowels.append("o")

    if "u" in string:

        vowels.append("u")

    return len(vowels)

       

print(vowelscount("aeiouaeiou"))