Defining a method final

[Jerzy Karczmarczuk]

Eric Brunel wrote:

> Python now have an "official" means to make attributes private by prefixing
> them with a double-underscore. And it *does* prevent their use or
> overloading:
> 
> class A:
>   def __private(self): pass
> class B(A):
>   pass
> o = B()
> o.__private()
> 
> results in:
> 
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
> AttributeError: B instance has no attribute '__private'

Some newbies may understand this wrongly. The attribute is still
accessible, it has just a different name: _A__private etc.

(You don't even need the class B to find out that 
o=A()
o.__private()

won't work. But launch dir(A) and look.)

Jerzy Karczmarczuk