In [1]:

    

l = [1,2,3]


    

In [15]:

    

class Book(object):
    def __init__(self,title,author,pages):
        print('a book has been created')
        self.title = title
        self.author = author
        self.pages = pages
        
#    def __str__(self):
#        return 'Title: %s, Author: %s, Pages: %s' %(self.title,self.author,self.pages)

#    def __len__(self):
#       return self.pages

    def __del__(self):
        print('a book is gone')

b = Book('python','jose',100)


    

    




a book has been created

In [17]:

    

del(b)


    

    




a book is gone

In [18]:

    

b.title


    

    




---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
<ipython-input-18-4ada4dac9a73> in <module>()
----> 1 b.title

NameError: name 'b' is not defined

In [ ]: