Install 3.9 on Ubuntu 21.04 - prefix & PYTHONPATH

[Gavin Jacobs]

I have a laptop computer with a fresh installation of Ubuntu desktop 21.04. I add the ppa and installed gnuradio; I got version 3.9.2.0 (Python 3.9.5). It runs fine from the GUI and the Terminal. Then I built a custom OOT block that I had written a year ago called Stream.Select - I can build it and install it and it shows up on the list of blocks, but at runtime it says:

ModuleNotFoundError: No module named 'stream'

Various pages suggest the problem may be related to PYTHONPATH and/or LDLIBRARY environment variables.

I tried to locate those with the following sequence:

gavin@RFSERVER04:~$ gnuradio-config-info --prefix

/.

gavin@RFSERVER04:~$ printenv PYTHONPATH

gavin@RFSERVER04:~$ printenv LDLIBRARY

gavin@RFSERVER04:~$

The output of the prefix is the root, which looks suspicious to me; and the output of the two printenv commands is nothing, also suspicious.

Am I on the right track?

Should the install of the binary package setup the prefix/PYTHONPATH/LDLIBRARY environment variables?

What should the environment variables be?

Thanks,

Gavin