grnboost2: No result, without error message

[ebelingm]

Hi,
I have successfully installed and run arboreto on a laptop PC. I tried to run an example based on the ex_01_grnboost2_local.ipynb notebook that you kindly provide, with a dataset very similar in size to the one you are using.
The box...
%%time
network = grnboost2(expression_data=ex_matrix,
tf_names=tf_names)
...appeared to run successfully, took about 3 minutes, printed the time report, and did not produce any error message whatsoever.
However, the next command
network.head()
...lead to the message that "network" does not exist (so it was not generated).
Any idea what could be the problem, please?
Thanks, best, M.