It's not a Dutch Thing. It's a Steve Majewski or Tim Peters Thing.
One of them once sent me a large sets of patches to the tutorial,
mostly intended to clean up minor typos or grammatical errors, or to
clarify possible misunderstandings. As part of the patch, they
smuggled a reference to the Trondheim Hammer Dance into an example.
When I asked them about it, they just smiled and said they liked to
see references to it in as many language tutorials as they could.
Wondering-whether-the-Trondheim-Hammer-Dance-exists-at-all-ly yours,
--Guido van Rossum, CWI, Amsterdam <mailto:Guido.van.Rossum@cwi.nl>
<http://www.cwi.nl/cwi/people/Guido.van.Rossum.html>