Putting a \layout block in a Scheme macro

[Jérôme Plût]

I want to make a Scheme macro \BlankStaff that outputs a single white
staff. (Optionnally, \BlankStaff #3 would output three of them, etc.
In particular, using “\include "blank-staff.ly"” is a non-solution).

A snippet does the white staff:
http://lilypond.org/doc/v2.19/Documentation/snippets/staff-notation#staff-notation-creating-blank-staves

However, this snippet uses a \layout { } block, which I am unable to
include in the #{ ... #} block of a Scheme function definition:

#(collect-music-for-book #{
  \score { \repeat unfold 12 { s1 } \break
  \layout { \indent = 0 \in
    \context { \Staff \remove "Bar_engraver" } } } #})

produces the following error:

scm/lily-library.scm:153:5:Wrong type argument in position 1 (expecting Prob):
#<Score>

So my question is this: how does the \layout{ } block translate to
Scheme?

Thanks,