I changed the code in the way you were suggesting. It was not working with sparktrials(). It only worked with Trials() which I believe means there is no distributed tuning as we don't call distributed training algorithms such as MLlib or Horovod and we only call single-machine algorithms.

How we can make sure if using Trials means distributed tuning or not?

You can take a look at the notebook at this address:

https://dbc-1dfc249d-eec7.cloud.databricks.com/?o=3298945606027707#notebook/1496814655941658/command...