How to install wildcard architecture packages on Ubuntu. Trying to add gives dpkg: error: architecture 'any', "all" is reserved and cannot be added

I expect to install packages created for different architecture onto my ubuntu server - and since those packages being architecture agnostic - they use a wild card

I want to add the wild-card such as "any" or "all" as a foreign architecture

I referred to https://wiki.debian.org/Multiarch/HOWTO. Since

But When I try to run command

enter code here
dpkg --add-architecture all
dpkg: error: architecture 'all' is reserved and 
cannot be added
root@arm-t2-imgtest-1-base-os-1:/opt/ucaastage# 
dpkg: error: architecture 'any' is reserved and 
cannot be addeddpkg: error: architecture 'any' is 
reserved and cannot be added

Based on below comment by @guiverc I referred to https://wiki.ubuntu.com/MultiarchHowto

As suggested in that I made an entry in /etc/dpkg/dpkg.cfg.d/multiarch as follows.. but after that when I run "pkg --print-foreign-architectures" gives an error "nknown option 'foreign-architecture'"

# cat /etc/dpkg/dpkg.cfg.d/multiarch
  foreign-architecture all

dpkg --print-foreign-architectures        dpkg: 
error: configuration error: 
/etc/dpkg/dpkg.cfg.d/multiarch:1: unknown 
option 'foreign-architecture'

apt update

 

Any suggestions ?

Since I did not find a direct answer to my question

Intially I though I needed to do something for "adding" the architecture "all" .so I install install time I added a suffix :all to package name and was happy that it installs well

apt install <my packagename>:all

And even more interesting - when using "all" wildcards - it is NOT necessary to specify the architecture suffix - so

apt install <my packagename> 

works just fine as far as you have a repository defined and have the packages with architecture="all" present