The famous, and wonderful (or not so wonderful if you dislike C++) GUI framework, Qt, has now added official support for the Python programming language. I have personally used PyQt5 and it was very easy to write a few lines of code and get a great looking user interface working. Qt is going to be using PySide2 for Python support:
As the industry’s most comprehensive user interface creation solution for Python, Qt for Python offers users a cross-platform environment for all of their development needs. By leveraging the APIs and expansive graphics libraries within Qt’s user interface development framework, Qt for Python provides developers with a fast and user-friendly platform that mirrors the agility that has become a hallmark of Python. In addition, Qt for Python is fully supported by the Qt Professional Services team of development experts and practitioners, as well as Qt’s large global community.