example python ppl with subroutines hp prime

[Liamtoh Resu]

I had problems trying to get the 20210428 emulator to run so I reverted back to the
2020 emulator.
The 20210428 CK is running fine.

I have the 20210505 firmware on the real hp prime.
I have not sent the updated version to the prime yet.

PPL and python are relatively new to me -- I am thinking about
backward compatibility.

Thanks.

edit: The program without the pre-declarations worked ok on the real hp prime.