wxPython is a GUI toolkit for the Python programming language. It allows Python programmers to Create programs with a robust, highly functional graphical user interface, simply and easily. It is implemented as a Python extension module (native code) that wraps the popular wxWidgets cross platform GUI library, which is written in C++.
Like Python and wxWidgets, wxPython is Open Source which means that it is free for anyone to use and the source code is available for anyone to look at and modify. Or anyone can contribute fixes or enhancements to the project.