This was attached to https://gna.org/task/?6847 by Michael Bieri
(https://gna.org/users/michaelbieri), in the zip file calc_modelfree.py_patch.tar.gz
(https://gna.org/support/download.php?file_id=7750).
Python modules wx and math are imported inti calc_modelfree.py.
The wx module is required to update the Log Window and the math to make exponential calculations.
