venv/lib/python3.10/site-packages/numpy/f2py/tests/src/routines/subrout.pyf

python module subrout ! in
    interface  ! in :subrout
        subroutine subrout_default(a,b,c) ! in :subrout:subrout.f
            fortranname subrout
            real*8 :: a
            real*8 :: b
            real*8, intent(out) :: c
        end subroutine subrout_default
    end interface
end python module subrout