How to access apm for io.atom.Atom flatpak

What is the proper way for accessing apm (Atom package manager) for flatpakked Atom?

I couldn't find the answer searching by DDG or Google. Slightly related question.

I can run Atom itself via:

flatpak run io.atom.Atom

One way I can run apm is via:

/var/lib/flatpak/app/

But this hardly seems normal. Is there some more reasonable/nice/clean/proper way to do this? Some things that don't work:

apm

flatpak run io.atom.Atom.apm

flatpak run io.atom.Apm

flatpak run io.atom.Atom --apm

/var/lib/flatpak/app/

The last path exists but tells me:

/var/lib/flatpak/app/ 5: exec: /app/bin/apm-real: not found

flatpak run --command=apm io.atom.Atom

or more specifically:

flatpak run --command=apm io.atom.Atom install packagename1 packagename2

The answer was in these two (1, 2) closed issues on io.atom.Atom github page.