[Zope] call by reference

Hi, for some external methods in zope i have do write some python scripts. Here my question: I want do a 'function - call by reference' in python. My function definition is like that: def foo(foo1,foo2): foo1=1 foo2=2 My intention is to call the function from an other function in the python script like def foo2(): x,y=2,3 foo(x,y) I know that python is working with seperate namespaces in case of function calls, but is there a work-around for this problem. ralph