How do I include a shell variable in my script?

[laredotornado]

Hi,

I'm running a Python script on a Solaris 9 machine, invoking the
Python script from ksh, if that matters.  There is an enviornment
variable, $JAVA_HOME, that I would like to include in my script,
replacing "/path/to/java/home'" with the value of $JAVA_HOME.

java_home='/path/to/java/home'

How do I do this?  If I need to pass a command line argument, so be
it, but I figure there is a more direct way to get the value.

Thanks, - Dave