Add support for `AssertExists` sequence steps
Add support for `AssertExists` sequence steps

(cherry picked from commit 7c620469d8ef6558def0ee6a30b83ef6607c8afa)
Signed-off-by: Nicolas Trangez <abbeee14574502be75498298fab55c152b9bac47@nicolast.be>

Incubaid/pyrakoon,Incubaid/pyrakoon