Build package for multiple platforms

[mikadoZero <mikadozero@yandex.com>]

I am preparing a patch for a package.  I am following the manual section
"14.6 Submitting Patches".  The fifth suggestion is to build the package
for multiple platforms.

I have added these to the system configuration file:
module: virtualization
package: qemu
service (taken from 14.6 Submitting Patches):

(service qemu-binfmt-service-type
 (qemu-binfmt-configuration
   (platforms (lookup-qemu-platforms "arm" "aarch64" "ppc" "mips64el"))
   (guix-support? #t)))

When I try to do a system reconfigure I get this error:

error: qemu-binfmt-service-type: unbound variable
hint: Did you forget a `use-modules' form?


The closest package I can find using `guix package -s` is proot but
adding the module linux and the package proot does not solve this error
message.

What should I do to get the system reconfiguration to work?