Well, I did so recently I'm mainly a front-end developer and was asked to develop a complete components [Full Stack] using a Python based CMS named Wagtail I did so with my experienced colleague who helped me a lot
I never used Python or Django before so everything was totally new to me I wrote the components and did the unit tests
The experience was truly amazing Oh my God I'm writing Python! and unit test it!
It really added a lot to me as a developer You learn different development paradigms other than what you used to
And it's funny cause to better learn JavaScript for example you need to learn other languages