Configure strict options for mypy and enable some of them

[jenshnielsen]

This explicitly configures some of mypys strict modes and enables a few more

Along the way this fixes what looks like 2 bugs in drivers

[codecov[bot]]

Codecov Report

Merging #4500 (346729e) into master (652ec54) will increase coverage by 0.00%. The diff coverage is n/a.

:exclamation: Current head 346729e differs from pull request most recent head 4adb919. Consider uploading reports for the commit 4adb919 to get more accurate results

@@           Coverage Diff           @@
##           master    #4500   +/-   ##
=======================================
  Coverage   67.99%   68.00%           
=======================================
  Files         299      295    -4     
  Lines       31429    31405   -24     
=======================================
- Hits        21370    21356   -14     
+ Misses      10059    10049   -10     

[jenshnielsen]

bors merge

[bors[bot]]

Merge conflict.