Hello! Thanks for visiting, 'check_params' i.e. problem in the pipeline section ? I recommend directly pull the notebook from repo then run and check. If you still get the error by running the notebook avaiable in the GitHub (https://github.com/suvoooo/Machine_Learning/blob/master/DecsTree/notebooks/Bank_Data_Analysis.ipynb), post a screenshot of the error. I believe it is the problem with the single and double underscores in __criterion and __max_depth.