ModuleNotFoundError: No module named 'tutorial'

Dear Gnuradio Community,

I built and installed tutorial module with qpsk demod block inside -
just from tutorial on
"https://wiki.gnuradio.org/index.php/Guided_Tutorial_GNU_Radio_in_C%2B%2B" .
I get an error:

  File "/home/ng/test.py", line 35, in <module>
    import tutorial
ModuleNotFoundError: No module named 'tutorial'


How can I fix that? I use GRC version 3.9.

Thanks for help

Niko