python GUI - which to use ?

[Johnse]

Hello,

Could someone advise me on what software or package that is free
and easy to use to build python GUI ?

I have use pyQT before and it works great, there are currently two
versions 4 and 5. Do both of them work for any version python ?

Please advise on a software or package that is free and easy to use to build python GUI.

Thanks !