PySide - Python language binding to Qt toolkit, compatible at the API level with PyQt . Unlike PyQt, PySide is available for free use in both open and closed, particularly commercial, projects, since it is licensed under the LGPL.
The project arose from the reluctance of the creators of PyQt to change the licensing policy for their project. PySide saw the light in August 2009, when the first public version was released. The main developers of PySide are Nokia programmers.
Source: https://habr.com/ru/post/114966/