[refactoring] remove this deprecated magic MARKER = nullobject()

5 jobs for topic/default/refactoring in 1 minute and 32 seconds (queued for 1 minute and 6 seconds)
Status Job ID Name Coverage
  Test
passed #24679
black

00:01:04

passed #24678
check-manifest

00:00:23

passed #24676
flake8

00:00:34

failed #24680
mypy

00:00:29

failed #24677
py3

00:01:08

 
Name Stage Failure
failed
mypy Test
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failed
py3 Test
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