Newbie import probelm..

[Diez B. Roggisch]

>>>> import invoker
>>>> x=invoker()
> Traceback (most recent call last):
>   File "<stdin>", line 1, in ?
> TypeError: 'module' object is not callable
>>>>

Try 

x=invoker.invoker()

The thing is that you declared the _class_ invoker in a file also invoker.
That makes 

import invoker

create a module named invoker, where all the things defined in invoker.py
are located. Try

>>>import invoker
>>>dir(invoker)

Regards,

Diez