Replace .format with f-strings
- [ ] solves few cases of  #29547


Hello @leandermaben! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:





There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2020-02-04 17:30:48 UTC