#Alphabet class
class Alphabet(object):

        def __init__(self, s):
            self.s = s

        def __str__(self):
            return "Before: " + str(self.s)


#Define your Vowels class here
class Vowels:
        def __init__(self,vowelList):
                self.vowelList = vowelList

        def __str__(self):
                return "Invoking the method in Vowels by passing the Alphabet objectnAfter: " + str(vowelList)

        def addVowels(self,a_obj):
                for letter in a_obj:
                    if letter in 'aeiou':
                        vowelList.append(letter)
                        l = ','.join(vowelList)

a1 = Alphabet('A,B,C,E,I')
print a1
b = Vowels(a1)
b.addVowels(a1)
print (a2)