Starting problem semi_automatic_tempest_example

[Ferditore]

When running an example from the gr-tempest / examples library, I have the following problems finding the default list item. The program swears and gives an error. How to deal with this?
I have GNU Radio Companion v3.8.2.0-119-gcba012fb, UHD 4.0.0.0-133-g7ec04886 and Volk 2.0. on a Virtual Machine Ubuntu 21.04 64-bit.

Below is the log from the GNU Radio terminal and the screen of the program

Generating: '/home/gnu/workarea/gr-tempest/examples/semi_automatic_tempest_example.py'
Executing: /usr/bin/python3 -u /home/gnu/workarea/gr-tempest/examples/semi_automatic_tempest_example.py
Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
Traceback (most recent call last):
File "/home/gnu/workarea/gr-tempest/examples/semi_automatic_tempest_example.py", line 438, in
main()
File "/home/gnu/workarea/gr-tempest/examples/semi_automatic_tempest_example.py", line 414, in main
tb = top_block_cls()
File "/home/gnu/workarea/gr-tempest/examples/semi_automatic_tempest_example.py", line 131, in init
self._mode_callback(self.mode)
File "/home/gnu/workarea/gr-tempest/examples/semi_automatic_tempest_example.py", line 130, in
self._mode_callback = lambda i: Qt.QMetaObject.invokeMethod(self._mode_combo_box, "setCurrentIndex", Qt.Q_ARG("int", self._mode_options.index(i)))
ValueError: 20 is not in list

Done (return code 1)

[bkerler]

Just replace "[x for x in range(len(modes))]" as option in the qt gui chooser