[mod_python] publisher handler questions

hello,

i am new to mod_python and python in general, so may be these are very
basic questions, but i still would appreciate your responses:

1. if i use the publisher handler, is there any way to hide some
function definitions in my .py file that is invoked through the
publisher handler so that the user could not call these functions by
navigating to their url?

2. in my .py file (that is invoked through the publisher handler
again) i define some global variables. i noticed that these variables
are initialised once. is this by design or just a coincidence? can i
rely on this behaviour?

thank you very much for any help
konstantin