In lesson2-download.ipynb it is said that you should not run the imageCleaner method in colab. I would like to let anyone who just started on lesson one that whatever issue was there when the notebook was made, it is no longer there. I run the imageCleaner on colab without any problem. you just need to remember to open another cell and run it maybe every 5 min so that your session does not timeout. for me I had a cell where I kept running a=5 at least every 5 min to keep the session a live.