[Cookbook][Test] fix sample code

[inelgnu]

Q	A
Doc fix?	yes
New docs?	no
Applies to	all

[wouterj]

Thank you for your work. 2 tips from me (for the next time):

• We can easily cherry pick commits into other branches, you don't need to create a new PR for that. @bicpi just told it you, so you do it right the next time :)
• Always create a new branch when editing something (when editing a file from this repo of a specific branch, you'll always create a patch-N branch in your own fork). When doing this, you can create multiple PRs at the same time.

[weaverryan]

Great fix - thanks @inalgnu!