Fix "Redefinition of exclude_checkers type from str to set"

redefined-variable-type
5 jobs for master in 2 minutes and 55 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #33759293
test:3.4

00:01:50

passed #33759294
test:3.5

00:02:27

passed #33759295
test:3.6

00:01:29

28.0%
 
  Deploy
passed #33759296
pages

00:00:26

passed pages:deploy

00:00:00