def __init__(self, title="", author=Author(), price=0, copies=0):
self.publik = Publication(title, price, copies)
self.__author = author
def __init__(self, title="", author=Author(), price=0, copies=0):
Publication.__init__(self, title, price, copies)
self.title = title
self.copies = copies
self.price = price
self.__author = author
def __init__(self, title="", author=author(), price=0, copies=0):
Publication.__init__(self, title, price, copies)
self.__author = author