Calling a class method

[Walter Brameld IV]

vsoler wrote:
> I have the following script:
> 
> class TTT(object):
>     def duplica(self):
>         self.data *= 2
>     def __init__(self, data):
>         self.data = data
>         TTT.duplica(self.data)
>     def __str__(self):
>         return str(self.data)
> 
> print
> obj=TTT(7)
> print obj
> 
> And I want 14 printed (twice 7)
> 
> I got the following error:
> TypeError: unbound method duplica() must be called with TTT instance
> as first argument (got int instance instead)
> 
> What am I doing wrong?

duplica() takes a 'self' parameter (a TTT instance), but you're calling 
it with self.data (an int instance).  Change this line:

TTT.duplica(self.data)

to this:

TTT.duplica(self)

and it will do what you want.