[f2py] passing var values

Hi,

I've got a problem with passing values of variables from Fortran to Python.
I've wrapped a Fortran Routine and pass a variable as a Parameter. I 
change the variable in Fortran and want, that Python knows the new value 
of the variable.

My code looks like:

 >>>variable=0
 >>>fortranmodule.sub(variable)
#in Fortran the value of the variable is changed to 1
 >>>print 'var',variable
var 0
#should be var  1

How can I realize, that I receive the correct value of the variable?

My file wrapp.pyf looks like:

            subroutine sub(variable)
                 integer intent(in,out) :: variable
             end subroutine sub

Maybe some one of you can give me some advise.
Thank you very much!

Greetings
Ben