Most of the time that is true with complex apps. Yes, so these depends need to be added as 'Requires:' in an rpm, or alternatively (but not officially Mandriva approved) be placed in the readme.txt, or built into the script that would install them.
Some python apps use a python or shell script to install the program from an extracted archive instead of an rpm.
python install.py
or
sh install.sh
Tunapie is a good example of this method to take a look at: tunapie.sourceforge.net
This tunapie program hasn't been touched since Sept. 2007, but it still works with Python 2.6.1 on Mandriva 2009.1.