If you need to get the python path used by plpython you can create a new function that prints out the system paths.
To get started, create a function called
python_path or whatever you want to call it:
CREATE FUNCTION python_path () RETURNS text AS $$ import sys return [p for p in sys.path] $$ LANGUAGE plpython3u;
Now you can list the paths by running a select query with the function:
For me the output looks like this: